| Variation of seed yield and the yield components, relationships between seed yield and its components, as well as relation between actual and potential seed yield of 28 Chinese registered alfalfa (Medicago saliva and M. varia) varieties were investigated under space sowing condition at the third and fourth year after planting from 2001 to 2002. The quality of seed harvested in 2001 was also evaluated. The results showed as follows:Variation of seed yield within-variety was larger than that between-variety. Average seed yield per plant for 28 varieties tested in 2001was 3.88g, varied from 0.71 to 23.4g within the largest variation variety, and varied from 1.20 to 8.0g among varieties. The within-variety and between-variety variance accounted for 86% and 14% of the total variance for seed yield, respectively. The average seed yield per plant among 10 varieties tested in 2002, selected based on higher seed yield in 2001,was 6.55g, varied from 0.78 to 37g within the largest variation variety, and varied from 5.30 to 9.08g among varieties. The between-variety and within-variety variance accounted for 3.2% and 96.8% of the total variance for seed yield, respectively.The 2 years results also showed that variation for each of the seed yield components within-variety were larger than that between-variety. The variation within varieties accounted for 67.5%~83.4% of total variance for seed yield components, while variance between varieties explained from 15.7% to 32.5% in 2001. The variation within varieties accounted for 52.7% ~ 98.7% and between varieties accounted for 1.3% to 47.3% of total variance for seed yield components in 2002. Taking results of 2002 as example: the range of each of yield components within the largest variation variety and between the varieties were: 114 ~13658 and 1123~ 1846 for inflorescences per plant, 5~19 and 7~9 for flower per inflorescence,5~ 210 and 28~48 for pods per shoot, 2~7 and 2~4 for seeds per pod, 1.13~2.21g and 1.57~1.74g for thousand seed weight, and 14-50 and 12-24 for shoots per plant,respectively.The simple correlation analysis showed that the seed yield significant positively correlated (p<0.05) to the seed yield components in different extent among the tested varieties. The number of variety which seed yield significantly correlated (p<0.05) to inflorescences per plant, flower per inflorescence, pods per shoot, seeds per pod, thousand seed weight and shoots per plant were 12,4,19,9 2 and 3, respectively in 2001; while in 2002 they were 5,1,6,3. The path -correlation analysis showed that pods per shoot had the largest direct effect on seed yield which followed by seed per pod and inflorescence per plant, while the other components had indirect effect on seed yield. Multiple regression equations of seed yield and its components were set up based on the path-correlation. They were Y=0. 102X1+0. 616X3+0. 313X4+0. 221X6 (R2=0.559) in 2001; and Y=0.973X, (R2=0.958) in 2002, respectively (X1 inflorescence per plant , X2 flower per inflorescence, X 3 pods per shoot, X4 seed per pod, X 5 thousand seed weight,shoots per plant, y seed yield plant).Percentage of actual seed yield accounted for potential seed yield (ASY/PSY) was less than 1% in most of varieties tested in 2 years. The percentage of ASY/PSY of 28 varieties varied from 0.16%( Wudi) to 1.07%( Gannong No. 2). The percentage of ASY/PSY of 10 varieties in 2002 varied from 0.29% (Xinmu No 1) to 0.81%( Gongnong No. 2). The clustering analysis was used to classify the seed potential productivity of 28 varieties tested in 2001, and 5 ranks were classified in this study.The evaluation of seed quality of 28 varieties harvested in 2001 indicated that non-significant differences were obtained from seed viability (germination plus hard seed), germination at the fourth day, abnormal seeding and dead seed. However hard seed was significantly different among 28 varieties. The average seed viability and hard seed of the tested varieties were 83% and 28%, respectively. For the hard seed content, hard seed of Gannong...
|
PDF Full Text Request