Genotype studies at ICRISAT

Genotype experiments carried out at ICRISAT Centre 1976-8 are decribed. A sorghum/pigeon pea experiment in 1977 examined 17 genotypes of pigeon pea with a standard sorghum genotype. Sorghum produced yields ranging from 82 to 99% of the sole-crop yield, but the differences were not significant. The pigeon pea genotypes achieved yields ranging from 36 to 73% of their sole-crop yields, giving total land equivalent ratios (LERs) up to 1.66. Although absolute pigeon pea yields in intercropping were dependent to some extent on sole-crop yields, this dependency only accounted for 40% of the variability in intercrop yields. There were indications that the most suitable pigeon pea plant type had a reasonably compact growth in the early stages to avoid competition from the sorghum but a spreading habit later to utilize resources after sorghum harvest. In 2 experiments, 3 pearl millet genotypes were examined in all combinations with 4 groundnut genotypes. Yield advantages up to 25-30% were achieved. It was concluded that the magnitude of the yield advantage was mainly determined by the groundnut genotype, whereas the proportion of groundnut yield to millet yield was mainly determined by the millet genotype. 3 sorghum/millet genotype experiments are described. In the 1st experiment 48 genotypes of pearl millet were grown with a standard sorghum genotype. Correlations between yield advantage and a range of millet plant characters did little to help identify which characters were most desirable in intercropping. The 2 later experiments examined 4 sorghum genotypes in combination with 4 millet genotypes. Yield advantages ranged up to just over 30%. These were considered to be very large advantages for 2 such similar crops; this combination is particularly worthy of further stud