Genotypic Variation in Cotton Genotypes for Low Phosphorus Tolerance and Efficiency Under Different Growth Conditions

Low phosphorus (P) availability is a major problem for cotton production. Identification of low P tolerant and efficient genotypes would best address these problems. In this regard, thirty cotton genotypes were categorized for dry matter production and P use efficiency (PUE) under low and normal P conditions. The results showed that cotton genotypes displayed considerable variations in root morphology, dry matter production, photosynthesis, PUE, and antioxidant system in response to low and normal P conditions. Genotypes Jimian169, Zhongzhimian2, and Lumianyan16 produced more dry matter have high PUE and were considered strong low P tolerant and efficient, whereas genotypes DES926, TM-1, and CCRI10 have low dry matter and PUE and were proved to be weak low P tolerant and inefficient. Based on various classification methods, genotypes Jimian169 and DES926 were considered strong and weak low P tolerant cotton genotypes, respectively. For most of the traits, the heritability was high, suggesting that selection under low P is more reliable than under the normal P condition. The use of the identified cotton genotypes and traits could improve cotton breeding activities and help to improve sustainable cotton production.