ENVIRONMENTAL AND AGRONOMIC EFFECTS ON THE GROWTH OF 4 PEANUT CULTIVARS IN A SUBTROPICAL ENVIRONMENT .2. DRY-MATTER PARTITIONING

The partitioning of dry matter between vegetative and reproductive yie ld components was analysed for four diverse peanut cultivars at a rang e of sowing dates and plant populations in sub-tropical Queensland, Au stralia. Rates of accumulation of pods (pod addition) varied significa ntly with both cultivar and sowing date. Within cultivars, much of thi s variation could be attributed to variation in crop growth rate durin g the critical pod addition period. The proportion of current assimila te distributed to pods depended on inherent cultivar characteristics a nd also correlated well with the current crop growth rate relative to the crop growth rate during pod addition (that is, with relative sourc e activity). Neither plant density nor spatial arrangement had any sig nificant effects on patterns of assimilate distribution. All cultivars appeared capable of remobilizing stored assimilate to maintain consta nt rates of pod yield increase despite fluctuations in crop growth rat e which might be expected to produce short term source limitations to pod yield accumulation. The harvest index (HI) increased linearly duri ng the entire pod fill period in all cultivars except the very early m aturing Spanish cultivar Chico. Neither density nor spatial arrangemen t affected rate of increase in HI except in Chico, where increased den sity produced increased rates of increase in HI. Variation in the rate of HI increase among sowing dates was small.