RICE GENOTYPING VARIATION FOR PHOSPHOURUS HARVEST INDEX AND UTLIZATION EFFICIENCIES

Abstract

A field experiment was conducted during kharif 2015 at the research farm of the ICAR–Indian Institute of Rice Research, Hyderabad, to evaluate the response of 30 rice genotypes to four phosphorus levels, viz., P0 (control), P20, P40 and P60. The experiment was conducted in a randomized block design with three replications. Varieties with high PUE under P0/P20 are ideal for resource-poor farmers and sustainable agriculture. Genotypes with high PHI under moderate phosphorus are valuable for improving grain nutrient content and yield stability. The study reveals that low to moderate phosphorus supply enhances utilization efficiency and harvest index, while higher doses reduce efficiency due to nutrient dilution. Varieties such as MAHSURI, KRH2, TRIGUNA, RPBIO226, and SUGANDHAMATI are promising for cultivation under phosphorus-limited conditions, as they combine high PUE with favorable PHI. At higher phosphorus levels (P40, P60), PHI declined sharply, indicating reduced efficiency of phosphorus allocation to grain. He CV values (12–17%) suggest moderate variability among genotypes. LSD (1%) values confirm significant differences among varieties, especially at lower phosphorus levels (P0, P20). Substantial differences in PUE and PHI highlight genetic diversity in phosphorus efficiency. Mahsuri, RP Bio226, KRH2, Triguna, PA6444 consistently performed well, suggesting potential as donor parents in breeding programs for phosphorus-efficient rice.