Genetic analysis of sweet pepper tolerance to low phosphorus availability in the soil

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1 Cop Beeding and Applied Biotechnology, v., n., p , Genetic analysis of sweet peppe toleance to low phosphous availability in the soil Valte Rodigues Oliveia * ; Vicente Wagne Dias Casali ; Cosme Damião Cuz 3 ; Calos Albeto Scapim and Nádja de Moua Pies Empesa de Pesquisa Agopecuáia de Minas Geais, Cento Tecnológico do Cento-Oeste, Caixa Postal 95, , Sete Lagoas-MG, Basil; Univesidade Fedeal de Viçosa, Depatamento de Fitotecnia, , Viçosa- MG, Basil; 3 Univesidade Fedeal de Viçosa, Depatamento de Biologia Geal, , Viçosa-MG, Basil; Univesidade Estadual de Maingá, Depatamento de Agonomia, , Maingá-PR, Basil. (*Coesponding Autho. voliva@net.em.com.b) ABSTRACT The objective of this study was to evaluate the mode of inheitance fo sweet peppe (Capsicum annuum L.) toleance to low P availability in soil, defined hee as the ability of plants to poduce elatively moe biomass (total dy weight) unde low P conditions. A complete diallel coss was used involving six peviously selected genotypes, thee toleant and thee intoleant to low P availability in soil. At 75 days afte sowing, total dy weight, shoot and oot dy weight, atio oot:shoot dy weight, and total P content in the plant wee evaluated. Thee wee no significant ecipocal diffeences in any of the assessed taits. The esults showed that genes contolling toleance to low P wee pedominantly but not exclusively dominant. Out of the thee toleant paents, two concentated dominant genes, and the othe, ecessive genes fo toleance to low P. The analysis of the genetic components of vaiation showed that both the additive and the dominant gene effects wee involved in the contol of all the chaacteistics, with a geate contibution fom the dominance to the genetic vaiability among paents and F hybids. The estimates of the boadsense heitabilities wee high, while the naow-sense wee in geneal compaatively low. Thei magnitudes, howeve, wee at a level that allowed successful selection. KEY WORDS: Capsicum annuum L., beeding, diallel, inheitance. INTRODUCTION The genus Capsicum, a membe of the solanaceae family, includes seveal impotant cop species. Sweet peppe (Capsicum annuum L.) is one the most impotant vegetable in Bazil, which also is used fo pocessing. The specie is found distibuted fom Mexico to Noth of South Ameica (Andews, 98). The sweet peppe flowe is nomally selfpollinated, although outcossing up to 9% has been epoted in Capsicum (Tanksley, 98). It is nomally gown as annuals, although may be maintained as peennial. In ecent decades, consideable effots have been spent towads the undestanding of the genetic contol of the efficient use of phosphous (P) by annual cops, especially in topical Ameica. Low P availability has been consideed one of the most limiting factos in plant gowth in highly weatheed topical soils (Sánchez and Salinas, 98). Besides the natual deficiency, P fetilizes ae not always available o affodable to fames and may be only maginally effective since the P fixation by Fe and Al oxides make applied and natual P unavailable to plants (Fageia et al., 988). Genetic impovement of P efficiency in sweet peppe may be a viable altenative o a complement to intensive fetilization of consideable inteest to beedes, fames and consumes. It can help to extend the life of the natual phosphate eseves and to educe the poduction costs and envionment pollution, which ae tageted in sustainable management pactices. The occuence of genotypic vaiability elated to low P toleance is cucial to beeding pogams aiming at developing moe efficient sweet peppe vaieties. Regading this aspect, the pesence of substantial genotypic vaiability in sweet peppe gemoplasm in the vegetative esponses to low P availability in soil is epoted by Oliveia et al. (999). 00, Sociedade Basileia de Melhoamento de Plantas

2 330 Cop Beeding and Applied Biotechnology, v., n., p , 00 Selection in segegating geneations following hybidization is a cuent pactice in sweet peppe beeding. Howeve, the efficacy of selection depends on the natue of the genetic systems which detemine the taits of inteest and the degee to which the envionmental effects influence thei expession (Cuz and Regazzi, 99). Knowledge of the type and elative impotance of the gene effects which act in the detemination of the taits will help sweet peppe beedes design effective beeding pogams fo developing impoved low P toleant vaieties. With this infomation, geate and faste genetic gains ae expected than those obtained though empiical beeding which ae based only on the obsevational ability of the beede. Among the biometics methods fo genetic analysis ae the diallel analysis methods, which allow an assessment of the genetic system that contols the tait unde study and supply useful infomation to paent choice fo hybidization, beeding methods and selection pocedues. Due to the amount of infomation they give on the inheitance of quantitative taits, the diallel coss pocedues poposed by Jinks and Hayman (953) and Hayman (95a, b) have been widely used in the undestanding of the genetic contol of the taits of a set of homozigous paents (Hayman, 95b). Examples of analysis of inheitance of toleance to limited P availability using this diallel analysis have been epoted in the liteatue (ice - Chaubey et al., 99; soybean - Speha, 995). Howeve, the inheitance of taits elated to low P toleance in sweet peepe has not been elucidated yet. In the pesent study the diallel analysis was used to investigate the mode of inheitance fo sweet peppe toleance to low P availability in the soil, in ode to povide infomation fo futue sweet peppe P efficiency beeding pogams. MATERIAL AND METHODS Six sweet peppe (Capsicum annuum L.) homozigous lines fom the Univesidade Fedeal of Viçosa Gemplasm Bank wee peviously chosen based on thei ability to poduce elatively moe biomass in low P soils (Oliveia et al., 999) and intecossed in a diallel system to obtain all possible hybid combinations, including ecipocals. Thee low P toleant genotypes (P--5-F, P- -5-F5 and P--03-F) and thee low P intoleant (P--50-F0, P--90- F and P--70-F) wee used as paents in the cosses. The populations (paents, F and F ecipocals), totalling 3 teatments wee oganized in a andomized complete block design with fou eplications. Each expeimental unit consisted of one pot with.5 dm 3 soil containing one plant pe pot. The soil used in the expeiment was a ed yellow podzolic (oxisol), accoding to the Bazilian soil classification, and had the following chemical popeties befoe the P teatment applications: ph 5. (:.5 soil-wate atio), extactable phosphous (P).0 mg kg -, extactable potassium (K) 0 mg kg -, extactable calcium (Ca).7 cmol c kg -, extactable magnesium (Mg) 0. cmol c kg -, extactable aluminum (Al) 0. cmol c kg - of soil. The soil was ai died, sieved and homogenized befoe eceiving a base fetilization with maco and mico nutients as follows: 00 mg P dm - 3 soil (tiple supephosphate), 00 mg N dm -3 soil (NH NO 3 ), 0 mg K dm -3 soil (K SO ), 80 mg S dm -3 soil (K SO, MgSO.7H O, ZnSO.7H O, CuSO ), 0.8 mg B dm -3 soil (H 3 BO 3 ),.33 mg Cu dm -3 soil (CuSO ), 3. mg Mn dm -3 soil (MnCl.H O), 0.5 mg Mo dm -3 soil ((NH ).Mo 7.O.H O) and mg Zn dm -3 soil (ZnSO.7H O). An : equivalent amount of Ca:Mg was supplied and CaCl.H O was used as a souce of Ca in addition to the tiple supephosphate. The compounds MgSO.7H O and MgCl.H O wee used as Mg souces. All nutients wee thooughly mixed with the soil in each individual pot befoe planting. Nitogen was supplied in its totality afte gemination at 0 days intevals. The dose of 00 mg P dm -3 soil was consideed low P availability in a pevious expeiment used to select the genotypes of this expeiment (Oliveia et al., 999). The expeiment was conducted in a geenhouse ove a week peiod, fom Febuay to May 99. Each pot was fequently wateed to maintain soil moistue 00, Sociedade Basileia de Melhoamento de Plantas

3 Cop Beeding and Applied Biotechnology, v., n., p , at appoximately 85% of field capacity thoughout the expeiment and monitoed by weighing pots at fou day intevals. Seventy five days afte sowing, the plants wee havested, sepaated into the leaves, stems and oots components, which wee died to constant weight in a foced-daft oven at about 70 ºC, weighed, milled, digested with a mixtue of nitic and pechloic acids (:) and coloimetically analyzed fo P (Baga and Defelipo, 97). The diallel analysis poposed by Jinks and Hayman (953) and Hayman (95a, b) was used to investigate the genetic contol of the total dy weight TDW (oots, stem and leaves), the shoot dy weight SDW (stem plus leaves), the oot dy weight (RDW), the atio between the oot and shoot dy weights (RRS), and the total P content in the plant (TPP). The diallel analysis was caied out afte checking fo adequacy of the genetic model, which implied homozygosity of the paents, diploid segegation, absence of multiple allelism, independent gene distibution among the paents, no ecipocal diffeences and absence of non-allelic inteactions. Initially, the analysis of vaiance of the diallel table was caied out using the statistical model Y s = m + J + J s + J s + K - K s + K s, whee J s = L + L + L s + L s (¹s), in ode to test the significance of the components a, b, b, b 3, c and d defined by Hayman (95a). The significance of the vaious souces of vaiation wee assessed by the F test. Howeve, since we would not expect that such vaiation souces would be influenced to the same extent by the envionment, the sums of the squaes of the specific eos wee obtained fo a, b, b, b, b 3, c and d, which ae the inteactions with the envionment of the coesponding main effects (Hayman, 95a; Mathe and Jinks, 98). The heteogeneity among the mean squaes fom the a, b, c, and d and b, b, and b 3 wee assessed by Batlett s test (Steel and Toie, 980). Since no ecipocal diffeences wee detected, the enties in the diallel table wee substituted by thei ecipocals means, and the following statistics wee estimated: V 0L0 (vaiance among paents), V (vaiance of the -th aay o column); V (mean of the vaiances of L the aays); W (vaiance of the means of the aays); W 0L0 (covaiance between the paents and thei offsping in the -th aay); (covaiance between the paents and the means of thei offsping); and (M L - M L0 ) (squae of the diffeence between the geneal mean (M L ) and the mean of the paents (M L0 )). Fitting of the data to the additivedominance model was checked using the values of W and V to assess the homogeneity of the W - V diffeences, by two tests: ) a linea egession of W on V and a test of the significance of the angula coefficient of the staight line (H 0 : b = vs H a : b ); and, ) weighing W and V by a 5º otation on the axles epesented by these statistics, and testing the angula coefficient of the staight line (H 0 : b = 0 vs H a : b 0). As the additive-dominance model was sufficient to explain the segegation patten obseved fo the assessed taits, the analysis of vaiance was intepeted and the statistics obtained fom the diallel table wee used to estimate the genetic vaiation components D, H, H, h, and F. The significance of the vaious components of vaiation was assessed by the t test. When t >.9, the component was consideed significant at the 0.05 pobability level (Singh and Chaudhay, 979). The elationships among the genetic vaiation components wee also used to estimate specific paametes and to assist in the intepetation of the esults. Additionally, the egession of W on V was used to obtain two futhe esults, the aveage degee of dominance and the elative genetic constitution of the homozygous paents. The coelation () between Y (mean of the paental values) and W + V, an indicato of the elationship among favoable alleles and dominance, was also calculated. Data wee analyzed using the Genes compute pogam (Cuz, 997). RESULTS AND DISCUSSION Nutitional efficiency has been defined in many ways in divese contexts (Föhse et al., 988; Clak, 990; Bailian et al., 99). In the pesent study, the P efficiency is defined as the ability of plants to poduce elatively moe biomass (total dy weight) unde low P availability in soil. Howeve, the inheitances of taits othe 00, Sociedade Basileia de Melhoamento de Plantas

4 33 Cop Beeding and Applied Biotechnology, v., n., p , 00 than just total dy weight - elevant and elated to toleance - wee also analyzed. The validity of the a simple additivedominance genetic model was confimed by the two sufficiency tests fo all the assessed taits (Table ), although TDW, SDW, RDW, and TPP equied data tansfomation to a logaithmic scale. Accoding to Hayman (95b) and Mathe and Jinks (98) the inteactions among non-allelic genes may fequently be eliminated by adjusting the measuing scale of the data, being the logaithmic tansfomation suitable when the limits of the scale equie gouping. Thee wee no ecipocal diffeences fo any of the taits assessed, as showed by the nonsignificance of the c and d souces of vaiation in the analysis of vaiance (Table ). The lack of ecipocal effects indicated that it makes little diffeence whethe a plant is used as a seed o pollen paent. Matenal effects in taits elated to toleance to low P and, o to othe mineal elements have also not been detected in othe species (Witeake et al., 97; Giodano et al., 98; Speha, 995). The absence of ecipocal effects and fit to the simple genetic model indicate that futhe estimations of vaious genetic components of toleance to low P ae justified when using this diallel analysis pocedue. Table - Sufficiency tests of the additive-dominant model based on the analysis of egession of W on V fo total dy weight, shoot dy weight, oot dy weight, atio oot:shoot dy weight and total P content in the plants. Chaacteistic Regession [ W = ( D H ) + bv ] b t (H o : b = ) b F = t (H o : b = 0) c Total dy weight 0.85± ns -0. ns Shoot dy weight 0.8± ns ns Root dy weight 0.5± ns -0.0 ns Root:shoot dy weight atio.0± ns -0.8 ns Plant total P content 0.99± ns ns ns not significant at the 0.05 pobability level ( b by t - test; c by F - test). means tansfomed to a logaithmic scale. The analysis of vaiance and the estimates of the genetic and non-genetic components of vaiation of total dy weight, shoot dy weight, oot dy weight, atio oot:shoot dy weight, and total P content in the plant ae pesented in Tables and 3, espectively. Significant a effects wee detected in the analysis of vaiance, indicating the pesence of genetic vaiability among the paental lines. Significant b indicated that dominance is pesent, and is pedominantly unidiectional fo all taits, accoding to the significance of the b souce of vaiation (Table ). The positive signal of the estimates of the contast between the means of n elements of the diallel table (M L ) and of the n paents (M L0 ) (Table ) indicate that the dominance deviations occued in the diection of the geate mean fo all taits. Besides dominance, additive vaiation also contibuted to 00, Sociedade Basileia de Melhoamento de Plantas

5 Cop Beeding and Applied Biotechnology, v., n., p , Table - Analysis of vaiance fo total dy weight (TDW), shoot dy weight (SDW), oot dy weight (RDW), atio oot:shoot dy weight (RRS) and total P content in the plant (TPP). Souces of vaiatino vaiation/ a Degees of Mean squaes feedom TDW SDW RDW RRS TPP Replications (B) Teatments ** 9.00** 5.3** 89.08**.0** a ** 70.** 9.79** 38.97** 8.8** b 5.83** 0.0**.33** 8.7**.98** b 53.3**.8** 8.99** 3.9**.93** b 5.8** 5.** 0.90**.5** 7.** b 3 9.9**.05** 8.7** 73.83** 5.53** c ns 0. ns 0.53 ns 3.3 ns 0. ns d ns 0.3 ns 0.5 ns 0. ns 0.3 ns Eo pooled Ba Bb Bb Bb Bb Bc Bd CV (%) ** significant at the 0.0 pobability level, by F test; ns not significant at the 0.05 pobability level; / All mean effects wee tested against the common eo vaiances, since heteogeneity of specific eos was not detected by the Batlett s test at 0.05 pobability level. the genetic vaiability among the paental lines and the F pogeny of the five taits assessed, as the dominance components, H, H, and h and the additive component D (Table 3) wee significantly diffeent fom zeo. Fo all taits, the negative and significant estimates of ( D - H ) demonstated the geate impotance of the vaiation associated with dominance effects and indicated the pesence of ovedominance among the alleles of non-fixed genes. This is confimed by a aveage degee of dominance above unity, estimated by the statistic ( H /D ) (Table ) and by the intecept of the egession of W on V (below the oigin) (Figues,, 3, and 5). In the tomato, the P-acquisition efficiency also exhibited significant dominance effects (Coltman et al., 987). Similaly, Fawole et al. (98) epoted that in beans the P utilization efficiency was contolled by genes with a significant dominance. 00, Sociedade Basileia de Melhoamento de Plantas

6 33 Cop Beeding and Applied Biotechnology, v., n., p , 00 Table 3 - Estimates of genetic and envionmental components of vaiation with thei espective standad eos fo total dy weight (TDW), shoot dy weight (SDW), oot dy weight (RDW), atio oot:shoot dy weight (RRS) and total P content in the plant (TPP). Component of vaiation Estimate ± standad eo (natue of component) TDW SDW RDW RRS TPP D (Additive) 3.83±0.78* 3.±0.75*.95±.03*.70±.37*.±0.7* H (Dominance).5±.99* 0.80±.9* 5.9±.*.70±.0*.5±.8* H (Dominance) 0.±.78* 9.98±.7* 3.7±.33* 3.±5.37* 0.±.* h (Dominance) 7.9±.0*.37±.5*.0±.57*.77±3.* 8.59±.08* F (Additive-dominance).3±.9 ns.33±.8 ns.±.5 ns 0.37±5.79 ns.5±.7 ns D - H -7.8±.75* -7.9±.8* -0.55±.9* -7.90±5.8* -7.8±.59* E (Envionmental) 0.5±0.30 ns 0.±0.8 ns 0.7±0.39 ns 3.5±0.89* 0.7±0.7 ns ns not significant (Singh and Chaudhay, 979); / The absolute value of the component divided by the espective standad eo, when >.9, is significant at the 0.05 pobability level. Table - Estimates of genetic paametes and diffeences between the means of the n values of the diallel table (M L ) and the n paental lines (M L0 ) fo total dy weight (TDW), shoot dy weight (SDW), oot dy weight (RDW), atio oot:shoot dy weight (RRS) and total P content in the plant (TPP). Genetic paamete Estimate ( ) /D TDW SDW RDW RRS TPP H (Dominance atio) K /K (Ratio of dominant to ecessive alleles) D R H (Asymety (Asymmety of of loci) loci) /H h /H (Numbe of effective factos with dominance) h BS (Heitability in the boad-sense) h NS (Heitability in the naow-sense) (Mean diection of dominance) M L M L0 00, Sociedade Basileia de Melhoamento de Plantas

7 Cop Beeding and Applied Biotechnology, v., n., p , W 3,98V W = =,357+ 0,89V W = 3,780V W =,3+ 0,8V W = P--5-F = P--5-F5 3 = P--03-F = P--50-F0 5 = P--90-F = P--70-F 8 0 W = P--5-F = P--5-F5 3 = P--03-F = P--50-F0 5 = P--90-F = P--70-F V - V Figue - The egession of W, on V, fo total dy weight. Figue - The egession of W, on V, fo shoot dy weight. 0 W W = = 5,7V 0,93+ 0,7V 30 W W = = 0,33V 9,5+,055V 8 0 W V = P--5-F = P--5-F5 3 = P--03-F = P--50-F0 5 = P--90-F = P--70-F 8 0 W V = P--5-F = P--5-F5 3 = P--03-F = P--50-F0 5 = P--90-F = P--70-F Figue 3 - The egession of W, on V, fo oot dy weight. Figue - The egession of W, on V, fo atio oot:shoot dy weight. W 0 - W W,507V = =,873+ 0,987V V = P--5-F = P--5-F5 3 = P--03-F = P--50-F0 5 = P--90-F = P--70-F Figue 5 - The egession of W, on V, fo total P content in the plant. In geneal, the significant b effects in the analysis of vaiance (Table ) and the atio H /H < 0.5 (Table ) fo all taits, demonstated that the positive and negative allelic fequencies in the goup of paental lines was asymetic, indicating an unequal popotion of positive an negative genes in the paents. The statistically non-significant F estimates (Table 3) indicated that thee ae equal mean fequencies of dominant and ecessive alleles in the loci affecting specific tait, egadless of thei inceasing o deceasing effects, although the values of K D /K R <.0 fo TDW, SDW, RDW and TPP (Table ) indicated that this equality should be intepeted with caution. The significance of the b 3 souce of vaiation in the analysis of vaiance (Table ), suggested the occuence of specific dominance deviations fo cetain F. The h /H atio (Table ) suggested that a small numbe of effective factos (genes o goups of genes) ae contolling the expession of the vaious taits elated with toleance to low P in sweet peppe. Since it povides no infomation about effective factos exhibiting little o no dominance, an undeestimation should be consideed (Cuz and Regazzi, 99). In maize, the expession of the chaacteistics elated with toleance to low P stess was contolled by a small numbe of genes (Silva et al., 99). The negative signal and modeate magnitude of the mean 00, Sociedade Basileia de Melhoamento de Plantas

8 33 Cop Beeding and Applied Biotechnology, v., n., p , 00 diection of dominance () fo TDW (Table ) indicated that the toleance to low P availability in soil, which is expessed by the geate TDW values, was conditioned pedominantly but not exclusively by dominant genes. This behavio can be confimed by compaing the ank of the means and the paental ode of dominance, given by (Table 5), whee lines and - low P toleants, and theefoe with a geate TDW - contained a numbe of dominant genes, and wee placed close to the oigin in the W on V egession gaph (Figue ). Howeve, line 3 with the thid geatest mean caied moe ecessive genes accoding to the means and dominance ank (Table 5) o the position on the egession gaph (Figue ). The distibution of the paental lines along the egession gaph demonstated that thee wee a ponounced genotypic dissimilaity among them unde a low P condition, even among the toleants. Simila to the TDW, the modeate estimate (and numeically negative) fo SDW, RDW, and TPP (Table ) demonstated that dominant genes pedominantly but not exclusively also contolled these taits. This behavio can be confimed by compaing the ank of the means and the paental ode of dominance (Table 5), whee lines and anked fist and showed lowe W + V values and consequently wee positioned neae the oigin of the egession line of W on V (Figues, 3 and 5). Howeve, line 3 - which also had a high mean fo these taits (Table 5) - caied pedominantly ecessive genes and was located fa fom the oigin of the egession line (Figues, 3 and 5). Fo RRS, the negative estimate and the high magnitude of the mean diection of dominance (Table ) indicated that exclusively dominant genes acted to incease RRS. The position of the paental lines along the W on V egession line (Figue ) shows that lines 3, and, with the geatest means (Table 5), wee located neae the oigin of the egession line, thus exhibiting a geate popotion of dominant genes, with ae, if any, ecessive genes fo high RRS. Lines, 5 and, with the lowest means (Table 5), wee positioned fathe fom the oigin of the egession line (Figue ), which indicated that they concentate ecessive genes. The values of the boad-sense heitability ( h BS) wee high fo all taits (Table ), pobably due the genetic divesity among paental lines and F and, also due the cultivation system used, wich allowed a good envionmental contol. The naow-sense heitability ( h NS) was low in geneal compaed to those of the boad-sense (Table ), but at a level that allowed selection fo low P toleance. The shap diffeence between h BS and h NS showed once again that both additive gene effects and dominance wee involved in low P toleance in sweet peppe. Similaly, estimates of heitability vaying fom modeate to high have also been obseved fo chaacteistics elated to low-p toleance in studies involving othe plant species (Fawole et al., 98; Chaubey et al., 99). The studies showed that toleance to low P in sweet peppe, defined as the ability to gow unde low P availability in soil, is genetically contolled. The pesence of additive and dominant gene effects suggested that beeding pogams fo development of cultivas which ae moe toleant to low P availability may be planned with a good chance of success. Howeve, fo futhe impovement of genotypes it is necessay to take into consideation the significant pesence of dominance gene effects to exploit in the population. It this aspect, the esults indicated that selection pocess in the pedigee method o its modifications should be elatively mild in the ealy geneations o else be defeed until an advanced geneation is eached with a geate degee of endogamy. On the othe hand, ecuent selection with the intemating of the supeio segegants should also be an altenative beeding pocedue to incease the fequencies of favoable alleles. The manifestation of ovedominance suggested that the exploitation of heteosis in F hybids may be an altenative, if thee is also supeioity in fuit yield and othe agonomic taits. CONCLUSIONS The toleance to low P in sweet peppe, defined as the ability of plants to poduce elatively moe biomass, was genetically contolled by additive and mainly dominant genes effects. Thee wee no matenal effects fo any of the taits elated to toleance to low P, theefoe, it makes little diffeence whethe a plant is used as a seed o pollen paent. The paents P--5-F, P- -5-F5 and P--03-F low P toleants, and theefoe with the geatest aveages of total dy weight when combined, may 00, Sociedade Basileia de Melhoamento de Plantas

9 Cop Beeding and Applied Biotechnology, v., n., p , poduce segegants still moe toleants than the paents and with a ponounced genotypic vaiability. ACKNOWLEDGEMENTS The authos would like to thank the financial suppot povided by the Coodenação de Apefeiçoamento de Pessoal de Nível Supeio (CAPES) and Fundação de Ampao à Pesquisa do Estado de Minas Geais (FAPEMIG). RESUMO Análise genética da toleância de pimentão ao baixo teo de fósfoo no solo O objetivo deste estudo foi avalia o modo de heança da toleância de pimentão (Capsicum annuum L.) a solo com baixo teo de fósfoo (P), definida como a capacidade das plantas em poduzi elativamente maio biomassa (massa seca total) em solo com baixo teo de P. Um dialelo completo envolvendo seis genótipos peviamente selecionados, tês toleantes e tês intoleantes ao baixo teo de P foi usado. Não houve difeenças ente cuzamentos ecípocos, em elação à massa seca total, bem como em elação à massa seca da pate aéea, massa seca de aízes, azão aiz:pate aéea e conteúdo total de P. Genes dominantes, pedominantemente, mas não exclusivamente contolaam a toleância ao baixo P. Dos tês paentais toleantes, dois concentaam genes dominantes e outo genes ecessivos. A análise dos componentes de vaiação genéticos evidenciaam que ambos os efeitos gênicos aditivo e de dominância estiveam envolvidos no contole de todas as caacteísticas, com maio contibuição da dominância paa a vaiabilidade genética ente paentais e F. As estimativas de hedabilidade no sentido amplo foam altas, enquanto, no sentido estito foam em geal baixas em elação às de sentido amplo. REFERENCES Andews, J. 98. Peppes: the domesticated capsicums. Univesity of Texas Pess, Austin. 70 p. Bailian, L.; McKeand, S.E. and Allen, H.L. 99. Genetic vaiation in nitogen use efficiency of loblolly pine seedlings. Foest Science. 37:3-. Baga, J.M. and Defelipo, B.V. 97. Deteminação espectofotomética de fósfoo em extatos de solos e mateial vegetal. Revista Cees. : Chaubey, C.N.; Senadhia, D. and Gegoio, G.B. 99. Genetic analysis of toleance fo phosphous deficiency in ice (Oyza sativa L.). Theoetical and Applied Genetics. 89: Clak, R.B Physiology of ceeals fo mineal nutient uptake, use, and efficiency. p.3-0. In: Baliga, V.C. and Duncan, R.R. (Eds.). Cops as enhances of nutient use. Academic Pess, San Diego. Coltman, R.R.; Gabelman, W.H.; Geloff, G.C. and Bata, S Genetics and physiology of low-phosphous toleance in a family deived fom two diffeentially adapted stains of tomato (Lycopesicon esculentum Mill.). p In: Gabelman, W.H. and Loughman, B.C. (Eds.). Genetic Aspects of Plant Mineal Nutition. Matinus Nijhoff Publishes, Dodecht. Cuz, C.D Pogama Genes. Aplicativo Computacional em Genética e Estatística. Viçosa. Editoa UFV. p. Cuz, C.D. and Regazzi, A.J. 99. Modelos Biométicos Aplicados ao Melhoamento Genético. Impensa Univesitáia, Viçosa. 390 p. Fageia, N.K.; Wight, R.J. and Baliga, V.C Rice cultiva evaluation fo phosphous use efficiency. Plant and Soil. : Fawole, I.; Gabelman, W.H.; Geloff, G.C. and Nodhein, E.V. 98. Heitability of efficiency in phosphous utilization in beans (Phaseolus vulgais L.) gown unde phosphous stess. Jounal of the Ameican Society fo Hoticultual Science. 07:9-97. Föhse, D.; Claassen, N. and Jungk, A Phosphous efficiency of plants. Plant and Soil. 0:0-09. Giodano, L.B.; Gabelman, W.H. and Geloff, G.C. 98. Inheitance of diffeences in calcium utilization by tomatoes unde lowcalcium stess. Jounal of the Ameican Society fo Hoticultual Science. 07:- 9. Hayman, B.I. 95a. The analysis of vaiance of diallel tables. Biometics. 0:35-. Hayman, B.I. 95b. The theoy and analysis of diallel cosses. Genetics. 39: , Sociedade Basileia de Melhoamento de Plantas

10 338 Cop Beeding and Applied Biotechnology, v., n., p , 00 Jinks, J.L. and Hayman, B.I The analysis of diallel cosses. Maize Genetics Coopeation Newslette. 7:8-5. Mathe, K. and Jinks, J.L. 98. Biometical Genetics. Chapman and Hall, London. 38 p. Oliveia, V.R.; Casali, V.W.D.; Peeia, P.R.G.; Cuz, C.D. and Pies, N.M Toleância de genótipos de pimentão ao baixo teo de fósfoo no solo. Bagantia. 58:5-39. Sánchez, P.A. and Salinas, J.G. 98. Low-input technology fo managing oxisols and ultisols in topical Ameica. Advances in Agonomy. 3:79-0. Silva, A.E.; Gabelman, W.H. and Coos, J.G. 99. Inheitance studies of low-phosphous toleance in maize (Zea mays L.), gown in a sand-alumina cultue medium. Plant and Soil. : Singh, R.K. and Chaudhay, B.D Biometical Methods in Quantitative Genetic Analysis. Kalyani Publishes, New Delhi. 30 p. Speha, C.R Diallel analysis fo mineal element absoption in topical adapted soybeans (Glycine max (L.) Meil). Theoetical and Applied Genetics. 90: Steel, R.G.D. and Toie, J.H Pinciples and Pocedues of Statistics. McGaw-Hill Book Company, New Yok. 33 p. Tanksley, S.D. 98. High ates of cosspollination in chile peppe. HotScience. 9: Witeake, G.; Geloff, G.C.; Gabelman, W.H. and Lindgen, D. 97. Intaspecific diffeences in gowth of beans at stess levels of phosphous. Jounal of the Ameican Society fo Hoticultual Science. 0:7-75. Received: Januay 30, 00; Accepted: July, , Sociedade Basileia de Melhoamento de Plantas