Maria José Granate

Predição de ganho genético com diferentes índices de seleção no milho pipoca CMS-43

Simultaneous breeding for expansion volume and grain yield in popcorn (Zea mays L.) is difficult because of negative correlation between these traits. The use of selection indexes allows to overcome this difficulty. In 1997/1998, at Embrapa-Centro Nacional de Pesquisa de Milho e Sorgo, in Sete Lagoas, MG, Brazil,166 half-sib families from CMS-43 popcorn were evaluated, using random blocks design. The selection indexes used were Smith and Hazel, Pesek & Baker, Elston and Williams. The selection index of Smith and Hazel allowed larger predicted gains in more traits, and on the contrary, the prediction using the selection index of Williams was insignificant. The use of selection indexes allows simultaneous prediction of gains in the two main traits.

Competição de clones de mandioquinha-salsa em quatro épocas de colheita

A major objective of arracacha breeding programs is to reduce the crop permanence in field. The yield of 11 clones and one cultivar of arracacha was evaluated at 187, 243, 306 and 370 days after planting in Araponga, Minas Gerais State, Brazil. The treatments were arranged in a factorial 12 x 4 scheme in randomized blocks design with three replications. Plant height, plant diameter, length of the longest root, diameter of the longest root, diameter of the thickest root, shoot yield, shoot number per plant, crown yield, aerial part yield, yield of marketable roots and yield of non-marketable roots were evaluated. The time each clone took to reach the average yield of Minas Gerais State (11 t ha-1) varied from 243 to 344 days and it was inferior to 365 days, the usual arracacha cycle in that region, for all the evaluated clones.. The clone BGH 5742 produced 13,46 t ha-1 after 243 days in field and presented the shortest estimated time to reach the Minas Gerais State average yield. The clones BGH 4550, BGH 5742, BGH 5746, BGH 5747, BGH 6417, BGH 6507, BGH 6521 and BGH 7607 produced less than the Minas Gerais State average yield after 306 days in field. Genotypic correlations of marketable root yield with other traits were low or null. Environmental correlations overcame the genotypic ones, and it evidenced a strong environmental influence on those plants.