Genetics of biochemical attributes regulating morpho-physiology of upland cotton under high temperature conditions

Background Cotton is a strategically important fibre crop for global textile industry.It profoundly impacts several countries’industrial and agricultural sectors.Sustainable cotton production is continuously threatened by the unpre-dictable changes in climate,specifically high temperatures.Breeding heat-tolerant,high-yielding cotton cultivars with wide adaptability to be grown in the regions with rising temperatures is one of the primary objectives of modern cotton breeding programmes.Therefore,the main objective of the current study is to figure out the effective breed-ing approach to imparting heat tolerance as well as the judicious utilization of commercially significant and stress-tolerant attributes in cotton breeding.Initially,the two most notable heat-susceptible(FH-115 and NIAB Kiran)and tolerant(IUB-13 and GH-Mubarak)cotton cultivars were spotted to develop filial and backcross populations to accom-plish the preceding study objectives.The heat tolerant cultivars were screened on the basis of various morphological(seed cotton yield per plant,ginning turnout percentage),physiological(pollen viability,cell membrane thermostabil-ity)and biochemical(peroxidase activity,proline content,hydrogen peroxide content)parameters.Results The results clearly exhibited that heat stress consequently had a detrimental impact on every studied plant trait,as revealed by the ability of crossing and their backcross populations to tolerate high temperatures.However,when considering overall yield,biochemical,and physiological traits,the IUB-13×FH-115 cross went over particularly well at both normal and high temperature conditions.Moreover,overall seed cotton yield per plant exhibited a posi-tive correlation with both pollen viability and antioxidant levels(POD activity and proline content).Conclusions Selection from segregation population and criteria involving pollen viability and antioxidant levels concluded to be an effective strategy for the screening of heat-tolerant cotton germplasms.Therefore,understanding acquired from this study can assist breeders identifying traits that should be prioritized in order to develop climate resilient cotton cultivars.

Review of oxidative stress and antioxidative defense mechanisms in Gossypium hirsutum L.in response to extreme abiotic conditions

Oxidative stress occurs when crop plants are exposed to extreme abiotic conditions that lead to the excessive production and accumulation of reactive oxygen species(ROS).Those extreme abiotic conditions or stresses include drought,high temperature,heavy metals,salinity,and ultraviolet radiation,and they cause yield and quality losses in crops.ROS are highly reactive species found in nature that can attack plant organelles,metabolites,and molecules by interrupting various metabolic pathways until cell death occurs.Plants have evolved defense mechanisms for the production of antioxidants to detoxify the ROS and to protect the plant against oxidative damage.Modern researches in crop plants revealed that low levels of ROS act as a signal which induces tolerance to environmental extremes by altering the expression of defensive genes.In this review,we summarized the processes involved in ROS production in response to several types of abiotic stress in cotton plants.Furthermore,we discussed the achievements in the understanding and improving oxidative stress tolerance in cotton in recent years.Researches related to plant oxidative stresses have shown excellent potential for the development of stress-tolerant crops.