Genetic Resources and Enhancement Program, International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Patancheru, 502 324, Andhra Pradesh.
Present address: 1Regional Research Station, Central Arid Zone Research Institute, Bangala Nagar, Bikaner, 334004, Rajasthan.
The influence of canopy structure and geometry on groundnut productivity was examined in two genotypes, TMV 2 and TMV 2-NLM. The latter is a mutant ofTMV 2 with narrow leaves. The two genotypes were grown on an alfisol field under irrigated and water deficit conditions during 1994–95 post-rainy and 1995 rainy seasons at ICRISAT centre. The crop growth rate (CGR) of TMV 2-NLM was greater than TMV 2 nnder adequately irrigated conditions by 11% during 1994–95 post-rainy and by 13% during 1995 rainy season. Under water deficit conditions, CGR of TMV 2-NLM was 32% higher than in TMV 2. TMV 2-NLM also had greater radiation use efficiency, 0.81 g mj−1 compared to 0.68 g mj−1 in TMV 2. The light extinction co-efficient of TMV 2-NLM was 0.51 as compared to 0.58 of TMV 2 under irrigated conditions, suggesting greater penetration of incident radiation into the canopy of TMV 2-NLM compared to that TMV 2. Although TMV 2-NLM produced greater total dry matter, the partitioning of dry matter to the pods (Pf) was less compared to TMV 2. Under water deficit conditions the Pf was reduced by 18% in TMV 2-NLM compared to 13% reduction in TMV 2. These results suggest scope for enhancing the crop productivity by tailoring canopy architecture. However, further research efforts are required to improve partitioning ability of groundnut genotype to match enhanced crop growth rates.
Canopy structure, crop growth rate, extinction coefficient, groundnut, partitioning, radiation use efficiency
