IMPROVEMENT OF THE PARTIALLY INBRED MAIZE PROGENITOR B-3A FOR LODGING TOLERANCE

Abstract

In outstanding maize hybrids (Zea mays L.), one of the parents may have an agronomic deficiency that limits its use. This research tested the lodging tolerance of the B-3A progenitor by taking advantage of intra-line variation through selfing generations, without modification of the combining ability for grain yield of the original line. One hundred and fifty self-sibs from progenitor S₃ B-3A were selected; each selected family was planted in single-row plots with 22 plants each. In each generation, selection for lodging tolerance within families was performed by pulling and shaking vigorously at the first three internodes of the stalk; only plants that did not bend, incline or torn from the root were selected. In the S₁₀ generation, 15 sub-lines were crossed to the tester B-4A, and 21 to the tester 6A. The recovered B-3A × B-4A and the original crosses were evaluated in uniform yield trials in Tepatitlán and Tlajomulco, Jalisco, and Santa María del Oro, Nayarit under rainfed conditions, and in Peña del Panal, Michoacán under irrigation. The recovered crosses B-3A × B-6A were planted in the same locations, except that Tepatitlán was exchanged for Iguala, Guerrero. Randomized complete blocks designs with two replications and single-row plots with 25 plants each were used in both yield trials. It was concluded that starting selection from an S₃ line for lodging resistance through consecutive selfing generations is not an efficient method, since at the S₁₀ generation only two sub-lines had 100 % less lodging than the original cross. Combining ability for grain yield of the B-3A line remained from S₃ through S₁₀ generation as no statistically significant differences in grain yield were observed between the original cross and the recovered one.