Abstract
Low phosphorus (P) availability is a major constraint for cotton production. Consequently, P-efficient genotypes can improve productivity under conditions where the higher application of P is not economical. This study was conducted to characterize cotton genotypes for P-use efficiency under various P concentrations (0, 10, 20, 40, 80, and 500 μM KH2PO4). The results showed large genotypic variation in five selected traits, such as root dry weight, shoot dry weight, photosynthetic activity, P-utilization efficiency, and P-uptake efficiency. Based on these five selected traits, the genotypes were grouped into three main classes as efficient, moderate efficient, and inefficient genotypes as proposed by different researchers. Most of the genotypes behaved in a similar pattern under different P concentrations. Among the genotypes, Xinluzao-49 and Xinluzao-48 were considered as P efficient while CCRI-64 and Yumian-21 as inefficient genotypes. However, the rest of the genotypes were considered as moderately P efficient. The results prove that a large genetic potential exists in cotton genotypes for P-use efficiency, and the use of P-efficient genotypes for cultivation will reduce the application of phosphatic fertilizers. Furthermore, the use of P-efficient genotypes will improve cotton breeding activities and help in improving the environmental sustainability of cotton production.
Highlights
Cotton is an important fiber crop grown worldwide [1] in arid and semi-arid regions [2]
Taking into consideration the constraints described above and the lack of information on genotypic variation of phosphorus use efficiency (PUE) in cotton, the aims of this study were (1) to evaluate the genotype variability for PUE in cotton genotypes under various P concentrations, and (2) to determine the relationships that exist between plant characteristics and PUE to facilitate the identification and choice of P-efficient genotypes
Different cotton genotypes showed a distinct response to P concentrations, with Xinluzao-49 showing the maximum and CCRI-64 the minimum shoot length (Table 1)
Summary
Cotton is an important fiber crop grown worldwide [1] in arid and semi-arid regions [2]. Limited availability of P triggers various physiological adaptive responses, such as increased root surface area and density, which helps in P uptake [5]. The variability in these responses indicates that cultivars having a greater capacity to grow in soils with low P availability could offer an alternative to P fertilizers [6]. The basic knowledge about the morphology, physiology, biochemical, and molecular mechanisms is essential to develop and screen P-efficient cotton genotypes. Identification and development of Agronomy 2019, 9, 689; doi:10.3390/agronomy9110689 www.mdpi.com/journal/agronomy
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