Seleção de genótipos de milho eficientes no uso de fósforo por meio de análise dialélica e análise AMMI-Biplot

Abstract

Phosphorus is a vital element for the survival of plants. The cerrado soils have low levels of this nutrient, requiring phosphate fertilizer for grain production, but the sources of phosphorus gradually come running out before that, it is important to identify efficient genotypes. The objectives of this study were to rate and select half sib progenies of maize with efficient use of phosphorus and through diallel crosses, evaluate the productive performance of hybrids by using AMMI-Biplot analysis, defining which are the best hybrids and genotypes more stable and responsive phosphorus use according to each environment studied. This work was divided into four steps, the first step was to obtain the 250 half sib progenies (PMI) from five different varieties, seeded on phosphorous stress condition. The second step was the evaluation of the 250 PMI selected with six witnesses in contrasting conditions of phosphate fertilizer at seeding high P (100 kg ha-1) and low P (0 kg ha-1) at Dourados-MS, on design of incomplete blocks in lattice 16x16 with two repetitions per level P. The individual and joint analysis of variance revealed different behavior of the progenies in the face of environmental oscillations and the PMI showed enough variability to advance the selection. Were selected seven progenies (213, 205, 233, 225, 30, 232 and 128) more efficient in the use of phosphorus to be crossed in diallel scheme. The third crop step was diallel crosses carried out in isolated field, obtaining 21 experimental hybrids. The experimental hybrids were evaluated in the fourth and final step in conjunction with parents and two witnesses, on design of randomized block design with three replications in Caarapó and Dourados, levels of high P and low P. Initially data were submitted to individual and joint analysis and the grain yield averages was realized individual and joint diallel analysis to determine the effects of combining ability to complement the study, AMMI analysis was used biplot allowing the graphical display for combining ability and stability of genotypes allocated in different environments. It is concluded that the variety has Al Avaré phosphor efficiency in use, as well as PMI 30 and 205. The hybrid H213x30 presented good stability to responded phosphate fertilizer, and was efficient for use, indicating that can be selected for the cultivation of farmers aimed at reducing the costs in agricultural inputs.