Growth and physiological responses of cotton (Gossypium hirsutum L.) cultivars with different phosphorus (P) efficiencies under variable P environment are poorly known. Therefore, this study explored effects of normal P [P + , 70 kg(P 2 O 5 ) ha -1 ] and without P (P − , 0 kg ha -1 ) on yield, growth, and physiology of different P-efficient cultivars [low-efficient Xinluzao 13 (L 1 ) and Xinluzao 26 (L 2 ); medium-efficient Xinluzao 10 (M 1 ) and Xinluzao 24 (M 2 ); high-efficient Zhongmiansuo 42 (H 1 ) and Xinluzao19 (H 2 )]. Cotton growth and yield was higher in H 1 and H 2 cultivars under P + compare to P − . Leaf photosynthesis, intercellular CO 2 concentration, stomatal conductance, and net assimilation rate increased under P + and in high-efficient cultivars. Greater Rubisco activity and higher soluble sugar content further promoted P uptake and utilization efficiency which resulted in a higher yield under normal P + than that at P − treatment. High-P-efficient cultivars have the potential to increase the yield by improving cotton growth and physiological attributes under P + .

Sweetpotato (Ipomoea batatas L.) has great potential for combating micronutrient malnutrition and vitamin A deficiency. To explore the potential of combining different micronutrients in the same cultivar through genetic improvement, we assessed the variation of Fe and Zn contents among 21 genotypes and 5 growing locations in the eastern region of China. Large genotype-dependent differences for Fe and Zn were found in the storage roots. The Fe content ranged from 2.68 to 4.64 mg/100 g dry weight basis (dwb), whereas the Zn content ranged from 2.92 to 6.95 mg/100 g dwb. The variation caused by genotypes, locations, and genotype × environmental interaction was highly significant for both Fe and Zn. No significant correlation was found between β-carotene and Fe and Zn contents in the storage roots. The results show that sweetpotato as a staple or co-staple food may provide a good proportion of bioavailable Fe and Zn for the nutritional requirements of human populations. It appears feasible to increase Fe and Zn in orange-fleshed storage roots through breeding of new varieties.