Capacidade de combinação e depressão por endogamia em populações de milho crioulo

AUTOR(ES)
DATA DE PUBLICAÇÃO

2010

RESUMO

The maize landraces are genotypes that have special features like wide genetic variability, which is noticeable through the color of grain, plant architecture and yield of their representatives. By presenting these different qualitative characteristics becomes important to perform a quantitative characterization of these genotypes for use in maize pre-breeding.The objective of this study was to evaluate the intersection of 28 landraces in testcross with two testers populations and to estimate the combining ability and inbreeding depression, promoting the largest amount of information for the characterization, conservation and use of this germplasm in the preoperative improvement. In the testcross were conducted in blocks with two replications in Pato Branco, Ponta Grossa and Londrina - PR. The plots had a line of 5 m with plant spacing of 0.20 m. Trials that evaluated the inbred progeny were conducted in Pato Branco and Ponta Grossa, through a split plot design. The variables were: days to flower (DF), plant height (HP) and ear (EH) and weight of grains (PG). The 56 intervarietal hybrids obtained by testcross among the 28 landraces and populations testers (PC 0201 and PC 0202) plus three checks were evaluated in the harvest of 2008/2009. The variable PG showed the highest GCA in populations GI 148 (1531.38 kg / ha) and 133 IM (963.13 kg/ha). It appears that the highest CEC were observed by crossing the tester PC 0202 with the following populations GI 151 (1115.23 kg / ha) and GI 173 (957,48 kg/ha), which also had the highest average production . Although the CEC estimate the population crossing in PC 0201 with 28 landraces was not as high as those observed in combinations with the 0202 PC, there is the highest means of production and the highest estimates for CEC stand out in combination with populaçaões the following: GI 152 (740.77 kg / ha), GI 088 (684.77 kg / ha) and GI 155 (655.77 kg / ha). Most inbreeding depression estimate for the variable was obtained by the PH population GI 152. And the people who showed the lowest was the GI 105 and GI 133 (-5%). For the variable EH highest values were observed in the GI 036. To the variable GY showed variation from 78 to 30.9%, the highest for the populations GI 048 (78%) and GI 028 (75.39%) also had higher values of d. Also for GY populations GI 158 (2077), GI 036 (1164) and GI 048 (1077) showed the largest estimates of contributions of additive effects, these values indicate that these populations can be used in the pre-breeding. The variables of plant architecture (PH and EH) and GY exhibited variability within groups of landraces per se and their testcross, allowing the use of these, with the aim of obtaining varieties or compounds with better architecture. Intervarietal hybrids show variation in the variable GY, allowing discrimination of crosses to obtain F1 more productive, with average heterosis of 57.9% of the combined PC 0201 x GI 148. For inbreeding depression note the predominance of additive effects in genetic control of the variables PH and EH. The inbreeding depression made by some people there is the likelihood of success of its use in the pre-breeding.

ASSUNTO(S)

milho - melhoramento genético milho híbrido - avaliação endogamia plantas - heterose endogamia corn plantas - heterose breeding corn hidrid corn breeding evaluation hidrid corn inbreeding evaluation inbreeding

ACESSO AO ARTIGO

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