Genetic Diversity And Pod Shattering Biological Characteristics Study Of Common Vetch (Vicia Sativa L.)

Common vetch(Vicia sativa L.)is an important annual,self-pollinating diploid forage legume.It has broad environmental adaptation including cold resistance,and has been widely distributed all over the world.The cultivated varieties Lanjian No.1,No.2 and No.3 in our research group alleviated the feed deficiency at early spring in Tibetan Plateau.However,most of the current varieties have the characteristic of high shattering rate and low seed yield.Thus,we collected 541 vetch accessions from 49 countries.Nine morphological characteristics,18 major agronomic traits,quantifying pod crack force and the transcriptional characteristics were investigated to understand the pod shattering mechanism with the aim of obtaining shattering-resistant,high yield varieties.The main results are as follows:1.The genetic diversity of 9 seed morphological characterizations of 541 vetch accessions was analyzed.Traits include: straight length,straight width,width to length ratio,curved length,curved width,perimeter,hilum length,100-seed weight and seed shape.It was shown that all the seed traits had significant(P < 0.05)genotype variation,indicating that there were potentially available genetic variations in these accessions.2.The genetic diversity of 18 major agronomic traits in 418 vetch accessions were analyzed for 2 consecutive years(2015-2016).It was found that all agronomic traits had significant(P<0.05)genotype variation.Under the condition of genotype × environment interaction,the shattering rate,plant dry weight is mainly controlled by genotype,and 100 grain weight is more susceptible to environmental impact.Based on the pattern analysis,three kinds of accessions with low shattering rate and high plant dry weight accessions were obtained.The results could be used for the breeding of new varieties with low shattering rate and high yield.3.The pod shattering rate was evaluated for 3 consecutive years(2013-2015).A total of 16 shattering-resistant accessions and 10 shattering-susceptible accessions were obtained.The mechanical force of the pod shattering was measured by the digital mechanical force gauge.The shattering-susceptible accessions shattering force was significantly lower than the shattering-resistant accessions shattering force(P < 0.01)(shattering-susceptible accessions shattering force was 2.16±0.29 N;shattering-resistant accessions shattering force was 9.29±1.83 N).4.The study found that the common vetch pod shattering first occurred in the pod ventral sutures.A total of 1,285 significantly differentially expressed unigenes(DEGs)were detected in the pod ventral sutures of shattering-susceptible and shattering-resistant,including 575 up-regulated and 710 down-regulated.Through the enzymatic activity analysis,the activity of polygalacturonase and cellulase in the ventral suture of the pod of shattering-susceptible accessions was significantly(P<0.05)higher than that of the shattering-resistant accessions.Analyses of GO and KEGG metabolic enrichment pathways indicated that 22 DEGs encoding cell wall modifications and hydrolases associated with pod shattering were highly expressed in shattering-susceptible accessions.