Effect of One- and Two-Eared Selection on Stalk Strength and Other Characters in Maize

Prolificacy associated with higher grain yield in maize (Zea mays L.) has been widely documented. However, one serious concern is that prolificacy appears associated with poor stalk strength and plant standability. The objective of this research was to compare stalk strength and other agronomic characters of one- and two-eared subpopulations derived from three maize populations (MoSQA(S7-H)C8 × Georgia Cow Corn [ACC]; MoSQB(S8-H)C8 × Georgia Cow Corn [BCC]:SI171). Entries were evaluated by using nine combinations of three levels of nitrogen (N) application (90, 180, and 270 kg ha 1 N) and three levels of plant density (35 800, 47 800, and 59 800 plants ha -1 ). Stalk crushing strength showed significant differences between one- and two-eared subpopulations for ACC and BCC, but it was not significant for SI171. One-eared subpopulations had higher rind penetrometer resistance than two-eared subpopulations for all populations. Two-eared selections generally resulted in poorer root and stalk strength. However, total grain yield of the two-eared subpopulations was significantly higher than that of the one-eared subpopulations for BCC and SI171, but not for ACC. Prolificacy has significant potential as a novel character for grain yield improvement in the future. Selection for prolificacy alone, representing indirect selection for grain yield, would produce undesirable effects on other agronomic characters, especially root and stalk strength. Concurrent improvement for total grain yield, prolificacy, and root and stalk strength by using a standardized, weighted selection index should be used to extract the real benefit of the prolific character.