Retention and shedding patterns of fruiting parts in four cotton genotypes (Gossypium hirsutum L.) under rainfed condition

Two low flowering cotton genotypes (AKH 081 & Bikaneri Nerma) and two high flowering types (SRT 1 & LRA 5166) were studied for the morpho-physiological traits in relation to abscission and seed cotton yield under rainfed condition. Leaf area was significantly higher in LRA 5166 followed by AKH 081, SRT 1 and Bikaneri Nerma. Relative water content, leaf water potential and solute potential showed no variation among the genotypes. Total shedding offruiting parts was significantly higher in Bikaneri Nerma followed SRT 1 and AKH 081. Lowest shedding was observed in LRA 5166. Physiological shedding showed a positive correlation to solute potential and negative correlation to stomatal resistance. These trends highlight the importance of plant internal water status and stomatal activity in determining abscission, particularly under rainfed situation. The negative correlations between shedding and bad boll opening as well as shedding due to other causes point out the possibility of physiological shedding of fruiting parts as influenced by boll load, intercompetition for nutrients and compensatory mechanism at canopy level during cotton ontogeny. Therefore, irrespective of the fruiting intensity of the genotypes only 10–12 harvestable bolls could be obtained under rainfed conditions of Nagpur, Maharashtra.