干旱胁迫对滴灌春小麦抗倒伏能力及产量的影响OA

To clarify the effects of drought stress during the growth period on lodging resistance and yield formation of drip-irrigated spring wheat,a split-plot experiment was conducted using a drought-insensitive cultivar Xinchun 6(XC6)and a drought-sensitive cultivar Xinchun 22(XC22)as the main plots,and drought stress treatments during the growth period as the subplots.Five treatments were established:normal irrigation(CK,75％-80％FC,where FC represents field capacity),mild drought at the tillering and jointing stages(T1 and J1,60％-65％FC),and moderate drought at the tillering and jointing stages(T2 and J2,45％-50％FC).The morphological traits of five elongated internodes(I1,I2,I3,I4,and I5)and the anatomical structure of the second basal internode were an-alyzed to evaluate the regulatory effects of drought stress on lodging resistance and yield formation in drip-irrigated spring wheat.The results showed that J1 significantly improved lodging resistance-re-lated traits in both cultivars(P＜0.05).Compared with CK,stem diameter,wall thickness,stem filling degree,and breaking strength of the five elongated internodes increased by 1.89％-10.90％,15.38％-56.41％,47.84％-175.70％,and 18.98％-58.74％,respectively,under J1.For the second basal internode,the numbers of large and small vascular bundles increased by 28.00％-34.62％and 28.57％-38.10％,respectively;the areas of large and small vascular bundles increased by 92.88％-98.79％and 45.60％-74.89％,respectively;and mechanical tissue thickness increased by 45.56％-59.11％.Consequently,the lodging resistance index of each internode increased by 26.67％-75.00％.Wall thickness,stem filling degree,breaking strength,and lodging resistance index all decreased from I1 to I5.Compared with XC22,XC6 showed obvious advantages in morphological traits,vascu-lar bundle traits,and mechanical tissue characteristics,resulting in 10.34％-80.00％higher lodging resistance index and more positive response to mild drought.Grain yield was highest under T1 for both cultivars,and XC6 yielded 5.74％more than XC22.Correlation and path analyses indicated that spike length and wall thickness of the I5 internode played greater roles in yield formation.For lodging resistance,breaking strength and wall thickness of the I1 internode had positive effects,whereas ex-cessive length of the I2 internode was unfavorable.These results indicate that,in the oasis agricultural region of Xinjiang,mild drought at the jointing stage(J1)is beneficial for improving stem lodging re-sistance of drip-irrigated spring wheat,whereas mild drought at the tillering stage(T1)is more con-ducive to yield improvement.