The yield of groundnut (Arachis hypogaea L.) grown in West African environments is often limited by high temperatures. We tested whether or not differences in the tolerance of groundnut genotypes to high temperature episodes are due to genotypic differences in the rates of dry matter partitioning to yield. A high temperature tolerant (HIT) and a high temperature sensitive (HTS) genotype were grown in a polyethylene-covered greenhouse (polytunnel) at 30/25°C (day/night) until after the start of pegging (49 d after planting, DAP). Then, cohorts of each genotype were exposed for 6 d to four different constant day temperatures between 30 and 50°C before returning to the common environment until harvest maturity (98 DAP). Total plant biomass and seed yield at 98 DAP were reduced by the hottest temperature episodes and were less in the HTS compared with the HIT genotype. Proportional reduction in biomass and seed yield due to high temperature stress was greater in the HTS than the HTT genotype. The root/total biomass ratio declined more rapidly after flowering in the HTS compared with the HTT genotype. The start of seed-filling was delayed by progressively hotter temperature episodes and was 11.7 d later in the HTS than the HTT genotype. However, the rate of increase in seed harvest index during seed filling was 0.0068 d−1 for both genotypes and was not affected by high temperature stress. We conclude that genotypic differences in the response of groundnut yield to episodes of high temperature stress were due to differences in the timing of seed filling rather than to genotypic differences in the rate of dry matter partitioning to fruits.
Wheeler, T.R.; Chatzialioglou, A.; Craufurd, P.Q.; Ellis, R.H.; Summerfield, R.J. Dry Matter Partitioning in Groundnut Exposed to High Temperature Stress. Crop Science (1997) 37 (5) 1507-1513. [DOI: 10.2135/cropsci1997.0011183X003700050016x]