Effects Of Seaweed Fertilizer And Seeding Rate On Pod Shattering Rate And Seed Yield Of Vicia Unijuga Var. Ganqing

Vicia unijuga var.ganqing is an excellent wild plant germplasm resource,which can be used as an important forage grass in the Qinghai-Tibet Plateau region,as well as an important grass species for replanting natural grassland and ecological restoration.However,the seed maturity is inconsistent,the pod is easy to shatter,the seed yield is low and unstable,which is not conducive to the seed production and large-scale cultivation and utilization.Seaweed fertilizer and seeding rate can reduce the pod shattering rate and improve seed yield.This study was conducted in Xiahe County,Gansu Province from 2021 to 2022 to investigate the effects of different seaweed fertilizer rating,seeding rates,and seed harvesting methods on the pod shattering and seed production of V.unijuga var.ganqing under different seeding rates.The main results are as follows:（1）Seaweed fertilizer significantly affected the growth and development,seed yield and pod shattering rate of V.unijuga var.ganqing.With the increase of seaweed fertilizer rating,the plant height,aboveground dry biomass and leaf area of V.unijuga var.ganqing increased first and then decreased,and they were the highest under the fertilizer spraying concentration of 5.0‰,which were 9.92%,14.47%,and 23.07%higher than those under the control,respectively.With the increase of the seaweed fertilizer rating,reproductive shoots per square meter,seeds per pod and harvested seed yield of V.unijuga var.ganqing increased first and then decreased,and they were the highest when the fertilizer spraying concentration is 5.0‰,which were 16.71%,13.90%,and 29.48%higher than those under the control,respectively.Path analysis showed that the contribution of reproductive shoots per square meter,inflorescences per reproductive shoot,and 1000-seeds weight to seed yield was the highest.With the increase of the concentration of seaweed fertilizer,pod shattering rate of V.unijuga var.ganqing decreased first and then increased,and the pod shattering rate was the lowest when the seaweed fertilizer spraying concentration was 2.5‰,which was significantly lower 23.27%than that under the control.There was a significant negative correlationship between pod shattering rate and harvested seed yield.（2）Seeding rate significantly affected the growth and development,seed yield,seed quality and pod shattering rate.With the increase of seeding rate,the aboveground dry biomass of V.unijuga var.ganqing showed an increasing trend,and reach to the highest when the seeding rate was 52.5 kg·hm^-2.With the increase of seeding rate,reproductive shoots per square meter,inflorescences per reproductive shoot,the harvested seed yield and seed germination rate increased first and then decreased,and they were the highest when the seeding rate was 37.5 kg·hm^-2.The pod shattering rate did not show a certain trend with the seeding rate,and was the lowest at the seeding rate of 22.5 kg·hm^-2.The interaction between fertilization and seeding rate significantly affected the harvested seed yield and 1000-seeds weight.The harvested seed yield was the highest when the seeding rate was 37.5 kg·hm^-2,which was 19.23%-97.65%higher than other treatments.The 1000-seeds weight was the highest when the seeding rate was 22.5 kg·hm^-2without fertilization.Path analysis showed that reproductive shoots per square meter and inflorescences per reproductive shoot had the highest contribution to seed yield.（3）Harvest times significantly affected the seed yield and quality of V.unijuga var.ganqing.The harvested seed yield,1000-seeds weight,seed germination potential,germination rate,germination index,vigor index,sprout length and radicle length were all the highest at the two harvest times,and were significantly higher than that at the one-time harvest treatment.The interaction between seeding rate and harvest times significantly affected the seed germination potential,germination index and vigor index.The seed germination potential was the highest when the seeding rate was 37.5 kg·hm^-2in two harvest times.The germination index and vigor index were the highest when the seeding rate was 22.5 kg·hm^-2in two harvest times.Based on the effects of different field management methods on seed production,the seeding rate of 37.5 kg·hm^-2and the concentration of seaweed fertilizer of 5.0‰were the most favorable for seed production of V.unijuga var.ganqing.