Climate change impacts crop production through the imposition of different abiotic and biotic stresses, and by altering the prevalence of pests and diseases. The wild relatives of crop plants exhibit enhanced tolerance to environmental stresses due to reduced severity of selection of agriculturally important traits. Wild bananas represent a largely untapped wealth of genetic diversity. Although some wild relatives of the banana crop have been screened for their tolerance to different biotic and abiotic stresses, many remain to be explored. The wild bananas show more hardiness and higher resilience to different stressors in comparison to their cultivated counterparts. They have been harnessed in banana improvement programmes to enhance stress tolerance and productivity. To utilise wild bananas for crop improvement, they need to be readily available to breeders. This warrants devising conservation strategies and the development and maintenance of centres from which different accessions can be procured. In this article, we have discussed some important biotic and abiotic stresses including banana wilt disease, Black Sigatoka disease, viral diseases, salt stress and drought stress where wild bananas are used for imparting tolerance. The conservation of wild bananas, related challenges and contemporary limitations related to their use for crop improvement has also been outlined. Bananas being most important food crop in the world and generally understudied, here, we present a comprehensive review of the use of wild relatives of banana and their related germplasm for the improvement of biotic and abiotic stress tolerance.

The continuously changing environment has led to devastating effects on the normal growth and development of plants. This necessitates the understanding of different components that can be involved in alleviating these effects. In the last two decades, nitric oxide (NO) has been largely focused on as a molecule whose endogenous production and exogenous supply lead to several molecular and physiological changes in plants under stressed conditions. Although its role as a signaling molecule in endogenous production has been largely discussed, its function in dealing with contemporary abiotic stress conditions on exogenous supply remains comparatively less explored. There is growing evidence that NO plays a critical role in many physiological processes; however, there is debate about the exact mechanism(s) through which NO lessens abiotic stress on external supply. In this review, we discuss the studies that were focused on observing the effect of exogenous NO on different abiotic stresses including heavy metal stress, element deficiency or toxicity stress, salt stress, drought stress, ultraviolet radiation stress, waterlogging stress, and chilling stress. Though the positive effects of endogenous NO have been discussed in brief in different sections, the focus of the review is to discuss the effects of exogenous NO on plant grown under abiotic stresses. Deciphering the underlying mechanism of exogenous NO treatment may open up new ideas that can suggest the successful application of NO in agricultural regions to reduce the damaging influences of different abiotic stresses.