Effect of Seed size on seedling vigour and seed yield

Seed size is an important physical indicator of seed quality that affects vegetative growth and is frequently related to yield, market grade factors and harvest efficiency. Genetic variation is the cause for variation in size of seed between varieties. Based on size, the seeds are classified as very large, large, medium, small and very small. This variation is due to flow of nutrients into the seed at the mother plant. Since seed coat and embryonic axis are the first to develop in a seed within a pod and accumulation of food reserve is occur later one. This variation is exerted in size, later on, on mobilization of food reserve to growing seedling. It has been reflected in many crop species and many varieties. For a successful crop production, the use of good quality seed is very essential which increases the yield by 15-20%. A wide array of different effects of seed size has been reported for seed germination, emergence and related agronomic aspects in many crop species.

Effect of large seed on seedling vigour:- Seed size is positively correlated with seed vigour, larger seeds tend to produce more vigorous seedling.Germination rate and seedling vigour index values increase with increase in seed size.In wheat ,Nagaraju(2001) observed higher plant height (97.83cm), number of leaves (7.58),stem girth (6.98cm) in plants rised by large size seed(passed through 3mm screen) compared to small size seed (passed through 2.8mm) plant height (90.50cm), number of leaves (6.53),stem girth (6.30cm) respectively.

Effect of large seed on seed yield:- Baalbaaki and Copeland (1997) reported that in wheat,seed size not only influence emergence and establishment but also affected yield components and ultimately grain yield.simmone et al.(2000) reported that size of seed has a strong influence on germination as well as growth and biomass increment of a plant.With increasing seed size spike production and density, number of tillers,main stem length, thousands kernel mass,test mass ,seed vigour and yield , therefore higher seed produces more yield than small seed.

Effect of small seed on seedling vigour:- Dar et al.(2002) have mentioned that small seed to medium sized ones produced better germination and seedling vigour than those bigger ones.peksen et al.(2004) show that cultivar with low seed weight had higher germination percentage than larger seed ones in pea(pisum sativum). Even the undergrade seed category was observed to be better for sowing purpose than small size of seed in mustard (Kumar et al,2005).Farhoudi and Matamedi (2010) proposed that small seed germinate faster and grew up higher under saline condition and that they could be preferred for use in saline soils to achieve better stands.

Conclusion: Seed size may be vary widely and crop species and the germination and growth environment, generally, the larger seeds have a higher seedling servival rate , larger biomass and adaptibility than small seeds under adverse conditions.

Writer: Ajit Yadav (Student, Bsc Ag 4th Sem, IAAS, Paklihawa Campus)