番茄IL渐渗系开花坐果期抗旱性评价OA

The flowering and fruit-setting period represents a critical water-sensitive stage for tomato.Screening drought-resistant germplasm specifically adapted to this phase is therefore of paramount importance for breeding.To sys-tematically evaluate the long-term drought tolerance of tomato introgression lines(ILs)at this key reproductive stage,a population of 49 ILs derived from Solanum pennellii(LA0716)and the cultivated tomato M82 was subjected to field-im-posed natural drought stress for 28 days,encompassing the transition from flowering to fruit setting.A multidimensional assessment was conducted by integrating evaluations of plant morphology and fruit yield with leaf physiological indica-tors,combined with a scoring method,principal component analysis(PCA),and K-means clustering analysis.The results showed that prolonged drought stress resulted in a yield reduction exceeding 50%for the majority of the ILs,coupled with significant oxidative damage.PCA extracted four principal components,and cluster analysis classified the 49 ILs in-to four distinct categories:Highly drought-tolerant(4 lines),moderately drought-tolerant(31 lines),drought-sensitive(12 lines),and special-response type(2 lines).Among them,the highly drought-tolerant line IL4-2 maintained optimal plant architecture under drought stress,exhibiting an 18.8%increase in yield per plant and stable fruit size compared to the well-watered control.At the physiological level,IL4-2 displayed no significant accumulation of H2O2,a decrease in MDA content,and significant increases the content of Pro and SS,alongside enhanced activity of SOD,POD,and CAT.In con-clusion,IL4-2 possesses outstanding comprehensive drought resistance during the flowering and fruit-setting period.Its adaptive mechanism likely involves the synergistic enhancement of both osmotic adjustment and the antioxidant defense system.Consequently,IL4-2 can serve as an important candidate germplasm resource for breeding drought-resistant toma-to cultivar.