Harvest Index in Spaced Populations and Grain Weight in Microplots as Indicators of Yielding Ability in Spring Wheat¹

Abstract

A set of 40 adapted homozygous spring wheat (Triticum aestivum L.) genotypes were grown under similar conditions of irrigation and high fertility utilizing large plots and microplots seeded at normal densities, and spaced plants (60 × 60 cm grid). The objective was to see how well spaced plant traits, especially grain weight and harvest index, and microplot yields predicted true yielding ability as measured with the large plots. Phenotypic correlation coefficients were calculated using genotype means.Microplot yield was highly correlated (r = 0.67 at the 1% level) with large plot yield but explained less than half of the variation between the genotypes. Much of the residual was probably related to the highly significant genotype Χ plot type interaction. With spaced planting, yield/plant was correlated (r = 033 at the 5% level) with crop yield. Better correlations with crop yield were obtained with plant and shoot harvest indices (r = 0.56 and 0.66, respectively, at the 1% level). No numerical components of yield measured on spaced plants gave better correlations with crop yield than yield per plant itself.These results emphasize the major effect that the degree of interplant competition, probably primarily for light in this case, has on the performance of a genotype. As the degree of competition declined going from crop plots to spaced plants, genotypes which can more fully occupy the increased space available were favored; thus, the performance of non‐erect genotypes improved noticeably relative to erect ones. We conclude that harvest index measurement offers promise as a predictor of yielding ability where the seed available is limited.

VARIATION IN MORPHOLOGICAL AND PHYSIOLOGICAL TRAITS ASSOCIATED WITH YIELD IN LIMNANTHES SPP.

“…The correlation of reproductive partitioning at 172 DFS with yield was highly signiflcant for L. douglasii entries, but not for the later-maturing L. alba where a larger value might have been obtained after allowing more time for seed filling. A close relationship between partitioning and yield has been used to advantage in numerous crop breeding programs, notably with cereals, where harvest index on an individual plant basis has served as a reliable predictor of high-density yield performance (Fischer & Kertesz, 1976).…”

Studies on endogenous hormonal changes during grain development in wheat genotypes

“…While, Syme (1972) and Fischer and Kertesz (1976) reported a close relationship of resource allocation to the grains with yield potential.…”

Evaluation of Bread Wheat (<i>Triticum aestivum</i> L.) Breeding Lines for Yield and Yield Related Characters in Horo Guduru Wollega Zone, Western Ethiopia

“…Belay et al (1993) reported strong associations of grain yield with thousand kernel weight and tiller number per plant in tetraploid wheat from Ethiopia. Fischer and Kertesz (1976) concluded from their experiment that harvest index is the best predictor of grain yield in wheat. Similarly, higher SPS are significantly associated with higher GY.…”