RECURRENT SELECTION IN THREE MAIZE POPULATIONS FOR THE MEXICAN SUBTROPICS

Abstract

Based on present and future priorities of maize production in Mexico, the Maize Breeding Program of the National Institute for Forestry, Agricultural and Livestock Research (INIFAP) defined a strategy of population maize improvement in the subtropical zone of México for the medium and long term. This research had as objective to assess the gain of selection for grain yield and correlated traits of economic interest in two tropical maize exotic populations (Pop 345 and Pop 347), and one subtropical adapted population (PABGI-PR). Pop 345 and Pop 347 were improved using the method of S2 lines, while PABGI-PR was improved with the full-sib method. The selection criteria were grain yield, and plant and ear traits. The selected synthetics of each population were evaluated, in independent trials, under rainfed conditions in Ameca, Jal., México. The experimental design used was randomized complete block design. The S₂ lines method was effective to increase grain yield (8.5 % per cycle), percentage of healthy ears (8.5 % per cycle), to reduce the number of days for silking (-2.3 % per cycle) and ear height (-4.8 % per cycle). Nevertheless, increasing grain yield in Pop 347 was not effective. In PABGI-PR population, the response of selection for grain yield was 9.3 % per cycle, and 1.6 % per cycle for percentage of healthy ears, but ear height increased 1.4 % per cycle in a correlated way. Prolificacy and percentage of healthy ears were the main traits to explain the gain for grain yield in the three populations.