Effect Of Density And Harvesting Period On Seed Yield And Quality Of Different Strains Of Medicago Ruthenica

In order to determine the appropriate plant spacing and harvesting period for different strains of Medicago ruthenica,seven seed fields with different plant spacing were planted at the Salazi experimental site in Inner Mongolia,and the seeds were harvested at three periods after the seed maturity stage.The optimum spacing of the seed fields of the three varieties and the suitable seed harvesting period were determined by comprehensive evaluation.The results are as follows.1.The fertility periods of the three Medicago ruthenica varieties differed considerably under natural conditions in Salazi.(1)The three Medicago ruthenica varieties differed considerably in their fertility under natural conditions in Salazi,with Mengnong No.1 being the latest in flowering and seed maturity and a late maturing variety with 165 d,while Zhilixing was the earliest in flowering and seed maturity and an early maturing variety with 148 d and Mengnong No.2 with 155 d.2.Among the three varieties,seed yield per plant and seed yield per unit area of Mengnong No.2 were more stable than the other two varieties at different densities,and had the highest thousand grain weight and the lowest pod split rate,which are important constituent factors affecting its seed yield.3.The seed yield of the three Medicago ruthenica varieties varied considerably at different plant spacings,with Zhilixing and Mengnong No.2 seeds producing the optimum plant spacing of 60cm-40cm;while Mengnong No.1 seeds produced the optimum plant spacing of 60cm-20 cm and plant spacing of 50cm-40 cm.4.The seed germination characteristics and seed yield composition factors of Medicago ruthenica differed somewhat between different harvesting periods,and a comprehensive analysis of seed harvesting yield and seed vigour determined that Zhilixing and Mengnong No.1 seeds are better harvested at late yellow maturity and early wilting stage,and the suitable seed harvesting periods are from early to mid-September,late September to mid-October respectively;while Mengnong No.1seeds are better harvested at late yellow maturity and early wilting stage.The appropriate harvesting period for Mengnong No.2 seeds is late yellow maturity(mid-September),while the appropriate harvesting period for Mengnong No.2 seeds is late yellow maturity(mid-September).