Response of oil and protein content to seed size in cotton(Gossypium hirsutum L., cv. Sahel)

This study was designed to identify the response of oil and protein content to non-heritable variation of seed size in cotton (Gossypium hirsutum L.). The experiment was conducted at Gorgan University of Agricultural Sciences, Gorgan, Iran in 2005. The results showed that germination and emergence increased linearity with seed size and R2 of these relationships were 92 and 89%, respectively. This means that larger seed had higher potential of germination and emergence. Also, there was a strong linear relationship between seed weight and oil content. Seed weight provided a better indication of oil content (R2=0.78) than protein content (R2=0.43). There are no considerable relationship between seed size and protein content of seed. The results of this study also showed a positive and significant correlation between seed weight and oil content (r=0.88**), germination percent (r=0.95**), germination index (r=0.84*), emergence percent (r=0.94**), and emergence index (r=0.88**). This results suggest that oil content, germination and emergence of cotton seed was largely affected by size of seeds. The effects of seed size where studied here are pure effects of size and is not confounded by other effects such as genotypic factors. This finding helps cotton breeders for the genetic improvement of germination and emergence along with oil and protein content of seeds.