Invasive Species Compendium

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Abstract

Drought resistance evolution of F1 and F2 hybrids from five climatic ecotypes Saccharum spontaneum L.

Abstract

Objective: Drought is an important abiotic factor which has a severe impact on yield and qualities of sugarcane production. Saccharum spontaneum L., a wild resource of sugarcane, possesses a series of characters such as strong stress resistance, excellent perennial root and wide adaptability. Therefore, study on the drought resistance of its progenies, screening of drought resistant germplasms could provide a basis for drought resistance parent selection and realize breakthrough in breeding new sugarcane cultivars. Method: In this study, thirty-six F1 and F2 individuals from five ecotypes S. spontaneum with Yunrui innovation parents, introduced species and domestic species were bucket-planted in the greenhouse used as materials. The materials were treated by artificial water stress including normal water supply (as control), mild water stress and severe water stress at the early elongation stage of sugarcane. Subsequently, seven physiological and biochemical indexes including plasma membrane permeability (PMP), contents of malondialdehyde (MDA), chlorophyll (CHL), soluble protein (Pr) and proline (Pro) content and activities of superoxide dismutase (SOD) and peroxidase (POD) in sugarcane leaves were measured. Eventually, the drought resistance of F1 and F2 generations was evaluated comprehensively using fuzzy membership function method, cluster and grey relational analysis. Result: Under water stress, the PMP, contents of MDA and proline, and the activities of SOD and POD raised, while the contents of CHL and PRO declined with different extents depending on sugarcane genotypes and stress degree. The results of fuzzy membership function analysis indicated that the drought resistance of S. spontaneum progeny varied was different under different water stress degrees, and the drought resistance of F1 generation was stronger than that of F2. The comprehensive drought resistance of individuals exceeded the parental up to 82% in F1, which was much higher than F2. The tested materials were classified into four groups under mild water stress by cluster analysis, and the drought resistance of groups I and II was the best, followed by group IV, and the worst was group III. Moreover, the individuals of group III were all from F2, and all the F1 individuals distributed in groups I, II and IV, respectively, which had strong drought resistance. Simultaneously, they could be divided into three groups under severe stress, and the F1 individuals excepted YGF108-473 were all distributed in groups I and III, which showed stronger drought resistance than group II. The grey relation analysis revealed that the correlation between physiological indexes and membership value was different because of water stress degree. Under mild stress, the correlation degree was in the order of PO D> SOD > PMP > MDA > Pr > CHL > Pro. But, the correlation degree under severe stress was in the order of SOD > Pr > CHL > POD > PMP > MDA > Pro. Conclusion: In all thirty-six tested materials, YGF108-536, YGF211-261, YG F108-391, YGF108-254, YGF211-90, YGF211-8, YGF211-258, YGF108-398, YGF108-543, YGF211-151 and YGF211-53 were exhibited strong resistance under water stress. These materials could be utilized emphatically in parent selection and drought resistance breeding. Furthermore, genetic performance of drought resistance had significant difference between F1 and F2 hybrids of S. spontaneum, and the drought resistance of F1 was stronger than that of F2. In addition, the drought resistance of S. spontaneum hybrids was no obvious correlation with paternal climate-type, geographic position and altitude. Based on the results of this study, PMP, contents of MDA and CHL, and activities of SOD and POD were good physiological and biochemical indicators with close correlation to drought resistance of sugarcane.