Abstract
Shoot biomass is considered a relevant component for crop yield, but relationships between biological productivity and grain yield in legume crops are usually difficult to establish. Two field experiments were carried out to investigate the relationships between grain yield, biomass production and N and P accumulation at reproductive stages of common bean (Phaseolus vulgaris) cultivars. Nine and 18 cultivars were grown on 16 m² plots in 1998 and 1999, respectively, with four replications. Crop biomass was sampled at four growth stages (flowering R6, pod setting R7, beginning of pod filling R8, and mid-pod filling R8.5), grain yield was measured at maturity, and N and P concentrations were determined in plant tissues. In both years, bean cultivars differed in grain yield, in root mass at R6 and R7 stages, and in shoot mass at R6 and R8.5, whereas at R7 and R8 differences in shoot mass were significant in 1998 only. In both years, grain yield did not correlate with shoot mass at R6 and R7 and with root mass at R6. Grain yield correlated with shoot mass at R8 in 1999 but not in 1998, with shoot mass at R8.5 and with root mass at R7 in both years. Path coefficient analysis indicated that shoot mass at R8.5 had a direct effect on grain yield in both years, that root mass at R7 had a direct effect on grain yield in 1998, and that in 1999 the amounts of N and P in shoots at R8.5 had indirect effects on grain yield via shoot mass at R8.5. A combined analysis of both experiments revealed that biomass accumulation, N and P in shoots at R6 and R7 as well as root mass at R6 were similar in both years. In 1998 however bean accumulated more root mass at R7 and more biomass and N and P in shoots at R8 and R8.5, resulting in a 57 % higher grain yield in 1998. This indicates that grain yield of different common bean cultivars is not intrinsically associated with vegetative vigor at flowering and that mechanisms during pod filling can strongly influence the final crop yield. The establishment of a profuse root system during pod setting, associated with the continuous N and P acquisition during early pod filling, seems to be relevant for higher grain yields of common bean.
Highlights
Common bean (Phaseolus vulgaris L.) represents a staple legume in many developing countries, but bean productivity is usually very low in most countries in Latin America and Africa, which requires agronomic and breeding efforts to improve grain yields
The purpose of this study was to investigate the relationships between grain yield, biomass production and accumulation of N and P at reproductive stages in field-grown common bean cultivars
Lynch & White (1992) observed marked differences in N budget of common bean cultivars between two field experiments with planting dates only 20 days apart
Summary
Common bean (Phaseolus vulgaris L.) represents a staple legume in many developing countries, but bean productivity is usually very low in most countries in Latin America and Africa, which requires agronomic and breeding efforts to improve grain yields. Yan & Wallace (1995) proposed that the shoot biomass, harvest index, and days to grain maturity are the three major physiological-genetic components for crop yield accumulation. The measurement of shoot biomass at flowering, underlying the rate of biomass accumulation across the vegetative and the reproductive stages, improves the understanding of the physiology of crop yield. It indicates the relative importance of the vegetative biomass for the potential yield capacity and the proportion of this biomass that is subsequently remobilized to the reproductive organs (Yan & Wallace, 1995)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
