Improved Plant Yield Efficiency is Essential for Maize Rainfed Production

Abstract

Plant yield efficiency reflects the single‐plant yield at low density that precludes interplant interference for resources. The role of plant yield efficiency in adaptation to water deficit was investigated in maize ( Zea mays L.). Also investigated was whether yield of space‐planted environments is transferable to densely seeded situations. Further, the correlation and genotype by environment (G × E) interaction of spaced and densely seeded plots were investigated. Thirty‐one lines and 31 crosses among them were tested in three locations under dense stand and the ultra low density of 0.74 plants m −2 as well as in normal and deficit irrigation treatments. The dense stand was 4.44 plants m −2 in the water deficit regime and 6.67 plants m −2 (lines) and 7.84 plants m −2 (hybrids) in the normal water treatment. Hybrids of greater plant yield efficiency were less sensitive to water shortage. Among four hybrids yielding the same at normally irrigated dense stand (11.50 Mg ha −1 ), yield loss due to water shortage was 46% for that of the lowest plant yield efficiency (645 g plant −1 ) and 17% for that of the highest plant yield efficiency (880 g plant −1 ). Correlations between hybrid plant yield efficiency and gas exchange water‐use efficiency in dense stand were significant. The low density ensured G × E interaction in the quantitative aspect only and thus was of higher heritability, placing emphasis on parental yield per se. Plant yield efficiency is a key element of hybrid ability to withstand water shortage and cope with environmental heterogeneity.