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Rotylenchulus reniformis Linford and Oliveira (reniform nematode) infestation has been a concerning issue in the Cotton Belt region of the United States for the past decade. Reniform nematode damage is more evident on cotton compared to other row crops in US Mid‐South because they share common edaphic conditions to sustain and develop. Annual cotton (Gossypium spp.) yield loss over the United States due to reniform nematode ranged from 1.14% to 2.37% in the past decade but exceeded 8% in the US Mid‐South States such as Mississippi. Yield losses due to nematode damage are mainly due to inconsistent control by cultural and chemical practices. In addition, there are location‐specific responses due to agronomic practices that result in its wide adaption. This review summarizes factors that influence reniform nematode infestations and the process of a plant infection, as well as management practices to mitigate nematode cotton production losses in the United States. The recent development of resistant cotton germplasm is a promising tool for reniform nematode management, although limited research has been conducted on the physiological mechanisms of resistance. In addition, understanding the role of host plant resistance and the interaction with other soilborne pathogens or abiotic stresses to control the nematode also is lacking. Future research must investigate best suited production practices specific to a region that could exploit the full potential of host plant resistance to minimize the risk of reniform nematode damage in cotton while protecting the environment. Core Ideas: Reniform nematode caused up to 8% annual loss to cotton production in the US Mid‐South over the last decade.Chemical and cultural practices showed inconsistent control of reniform nematode damage.The recently released reniform nematode‐resistant varieties are invaluable for cotton producers, industry, and researchers. [ABSTRACT FROM AUTHOR]

Insufficient moisture availability often limits soybean [Glycine max (L.) Merr.] yield. Carbon isotope ratio (δ13C) provides an integrated measure of water use efficiency in C3 plants due to its substantial genetic variance, high heritability, and small genotype × environment interaction (G × E). The objective of this study was to identify quantitative trait loci (QTLs) associated with δ13C using a recombinant inbred line population derived from a cross between 'KS4895' and 'Jackson'. The field experiment was conducted in five environments to evaluate δ13C under rainfed and irrigated conditions. Analysis of variance of δ13C averaged over environment and irrigation treatment showed significant effects of genotype (G), environment (E), and G × E interactions. Heritability of δ13C in different environments and irrigation treatments ranged from 66 to 79%. Averaged over environments and irrigation treatments, heritability was 83%. A total of 24 QTLs associated with δ13C were identified and clustered in nine genomic regions on seven chromosomes. The QTL clusters on Gm05 (1), Gm06 (2) and Gm20 (1) were detected across different environments and irrigation regimes. Collectively, these four QTL clusters accounted for 55% of the phenotypic variation in δ13C. The QTLs on Gm06 and Gm20 also showed additive × additive epistasis that contributed approximately 4.2% to the total phenotypic variation. Several identified δ13C QTLs overlapped with QTLs associated with other physiological traits related to plant water status, biological nitrogen fixation, and plant morphology. The identified genomic regions may be an important resource in genomic selection studies to improve drought tolerance in soybean. [ABSTRACT FROM AUTHOR]