بررسي چند جنيني در بذور نارنج CITRUS AURANTIUM جمع آوري شده از نقاط مختلف استان هاي مازندران و گلستان

Study of polyembryogenesis in orange (citrus aurantinum) seeds collected from different regions of Mazandaran and Golestan provinces

In order to evaluate the effects of site (climatic factors) on polyembryogenesis and vegetative embryogenesis phenomenon and determination of its relationship with seed starch content in orange (citrus aurantinum), orange seeds were collected from four separate sites located in North of Iran including Tonkabon, Babol, Sari and Gorgan. Germination percentage and rate, polyembryogeny percentage and starch contents of collected seeds were measured. Results indicated that collection site had significant effects on all studied characteristics except germination rate. The highest measured values for all mentioned traits (except germination rate) were belonged to Tonkabonʹs seeds, as statistical differences between achieved means for germination rate and percentage of Tonkabonʹs seeds were significantly different than other collected seeds. Germination percentageof Sari, Gorgan and Babol seeds decreased ll, 14.8, 15%, respectively in comparison with Tonkabonʹs seeds, while these values for polyembryony percentage werel4.6, 22.6 and 26.9%, respectively. Correlation coefficients between climatic factors and studied traits indicated that higher precipitation in Tonkabon, specially during summer has been one of important affecting factors on studied traits in this site. Also, correlation coefficient between germination rate and polyembryony with seed starch percentage were 0.7 and 0.65, respectively. A high correlation coefficient also was achieved between germination rate and polyembryony percentage (Rʹ =0.83*, while correlation coefficients between germination rate and seed starch percentage & germination rate were not significant). Results indicated that highest positive effect on germination percentage belonged to maximum temperature, while minimum temperature didnʹt affect it. Precipitation quantity had negative effect on germination percentage. Also, mean temperature had negative effect on starch accumulation in seeds, while precipitation effect was positive and significant. Polyembryony also had a negative and significant correlation with maximum temperature, but a positive correlation with precipitation.