Variation in harvest index of maize (Zea mays) and common bean (Phaseolus vulgaris) grown in a marginal rainfall area of Kenya

Abstract

S U M M A R YMaize {Zea mays L.) and common bean (Phaseolus vulgaris L.) were grown in five seasons, beginning in the long rains 1990 and ending in the short rains 1992, at Kiboko, Kenya under a range of different management conditions (N fertilization, irrigation, population density and intercropping). Seed weight was plotted against total dry weight to determine harvest index for both crops. For bean the intercept of this relationship for each experiment, with one exception, was not significantly different from zero, so that the slopes of the regressions were the harvest indices. Harvest indices for bean varied more between seasons (0-38-0-85) than from the effects of management practices (0-53-0-71). Over all seasons and treatments, the index for bean did not vary systematically with crop weight, and averaged 0-50. By contrast, a similar analysis for maize over all seasons and treatments, showed that the harvest index varied with crop dry weight, approaching an asymptotic value as dry weight increased. The regression intercepts for the different experiments were significantly different from each other, and in three cases differed significantly from zero. Therefore, although the slopes for the different experiments were parallel, they did not always represent the harvest index.ixirnnniifTrnxi decreases. Harvest index may also increase or decrease

The Role of Harvest Index in Improving Crop Productivity: A Review

“…It is an appropriate trait to target for increasing yield potentials for crop breeding activities (Sadras and Richards, 2014). The highest seed yields are often associated with high HIs which then become an important selection criterion in plant breeding (Pilbeam, 1996). A more comprehensive understanding of harvest index and the basis upon which variations in harvest index are achieved among different genotypes would be of considerable advantage to food production systems.…”

Seasonal variations in harvest index and bacoside A contents amongst accessions of Bacopa monnieri (L.) Wettst. collected from wild populations

“…Identification of such high yielding accession is important for cultivation and production of bacoside A. The variation in the biomass and HI has been reported earlier in many crops (Gilbert et al 2006;White and Wilson 2006;Pilbeam 1996;Scully and Wallace 1990). These authors reported that increase in harvest index is due to the increase in biomass of the plant.…”

Yield Responses of Maize (Zea maysL.) and Successive Potato (Solanum tuberosumL.) Crops to Maize Stover co-compostedwith Calliandra CalothyrsusMeisn Green Manure

“…5. Besides the effect of the genetic impact, soil nutrient availability, soil water limitation or excess, and rainfall distribution are some of the abiotic factors that control crop HI variability [68][69][70]. In addition, maize (Zea mays L.) grown under temperate conditions show higher HI values than under tropical conditions, because of shorter grain-filling period in the tropics due to water limitation [66].…”