A comparison of drought resistance of three zoysiagrasses and their new strains induced by ⁶⁰Co-γ radiation

Objective To evaluate the differences of drought resistance of three zoysiagarasses, Zoysia japonica, and their new strains induced by ⁶⁰Co-γ radiation.

Method Three zoysiagrasses including Lanyin No.Ⅲ (LY), ZS-1 (ZS) and ZS-SJZ (ZSS), and their six new strains were cultivated in pots under the drought stress condition.The relative water content, relative electrical conductivity, proline content and total soluble sugar content of leaves were measured on the 3rd, 9th and 15th day after the drought stress treatment.The turfgrass coverage and color were observed and evaluated during the drought stress.

Result and conclusion With the increase of drought stress, the relative water content of leaves decreased gradually and turfgrass coverage and color scores also reduced, whereas the proline content, total soluble sugar content and relative electrical conductivity of leaves had an upward trend.Through the comprehensive evaluation of drought resistance with subordinate function weights coefficient of standard deviation, the drought resistance ability ranks of the tested materials were as follows:ZSS-5 > ZS-3 > LY > LY-2 > ZS > ZS-4 > LY-1 > ZSS-6 > ZSS, which demonstrated that the drought resistance abilities of new strains ZSS-5, ZSS-6 and ZS-3 were stronger than those of their parents.The radiation breeding is an effective way to breed new drought-resistant zoysiagrass varieties.