Phosphorus Efficiency among Selected Sorghum (Sorghum Bicolor L. Moench) Lines and Segregating Families
Sorghum (Sorghum bicolor (L.) Moench) is an important food security crop in Kenya but its production is limited by low available soil phosphorus (P) amongst other factors. This is because its cultivation is mainly carried out by resource limited peasant farmers in marginal agricultural areas that are characterized by soils with very low P levels. This study was carried out to evaluate Kenyan sorghums that are tolerant to low P levels. A P efficient sorghum line, MCSR L6 was crossed with a P ineffi cient but P responsive line, MCSR N64. The resultant F1 seed was selfed to produce F2 seed that was used in the current study. Six F2 segregating families were characterized for P efficiency in the field with low available P (3 mg of P/kg of soil). MCSR L6 yielded better than MCSR N64, under low available P, but showed poor response to P application in the field. The F2 sorghum families segregated in terms of days to 50 % flowering, plant height, leaf number per plant, tiller number and grain yield. Based on grain yield, the six sorghum families were classified into four groups; efficient and responsive to P, inefficient and responsive to P, efficient and non -responsive to P, and inefficient and non -responsive to P. The results indicate that the F2 progeny show genetic variability for P efficiency and responsiveness to additional P, implying that these two traits were successfully transferred from the parents to the progenies
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