SEED AND SEEDLING CHARACTERIZATION, CALLUS INDUCTION AND BIOMOLECULAR ANALYSIS OF TWIN GRAIN RICE

Abstract

Twin grain rice is newly found genotypes. A Twin grain rice seed contains two or three grains with similar number of embryo and endosperm. Thousand Seeds weight of Twin grain rice was 29.76g whereas the nearest weight 18.75g (Bolder) among the genotypes. Seed’s size was large like Badshabhog, Rangit and Binadhan-7. Germination percentages were 61.3 and 70.1 on sand and soil, respectively with single seedling but at MS medium 100% germination with two to three seedlings from a single seed. Reserved food was not available in endosperm. Another experiment was under taken to develop a protocol for callus induction of Twin grain rice. Different concentrations of 2,4-D with MS medium was used. Best callus induction was recorded 82.5% at 2 mgL” 2,4-D. The highest callus size and weight were obtained at 2.5 mgL” 2,4-D (4.74mm) and 2 mgL’! 2,4-D (78.03 mg), respectively. 2,4-D at 2 mg L” and 2.5 mgL” with MS medium were better for callus formation of Twin grain rice. Random amplified polymorphic DNA (RAPD) technique was used to detect genetical diversity and relation assessment among ten rice genotypes. The highest number (10) bands were found in OPAB 09 primer. The highest Nei’s gene diversity and Shannon's Information index was 0.0407 and 0.0568, respectively. The lowest Intra-germplasm similarity index and genetic variability were in Twin grain rice. The highest Inter-germplasm similarity index (100%) was observed Kataribhog vs. Bolder, Zirakatari vs. BRRI dhan-34 and Kataribhog vs. Binadhan-7. Crossing between Twin grain rice and Kataribhog or Rangit or BINAdhan-7 would be done for their lowest Intergermplasm similarity index. The highest genetic distance was observed Zirakatari Vs BRRI dhan-34 and Kataribhog Vs Bolder. The Unweighted Pair Group Method of Arithmetic Means (UPGMA) the 10 genotypes of Rice were grouped into 2 main clusters. The lowest genetic variation was present in Twin grain rice and Chikonsorna and those formed sub cluster- I in cluster-I. Twin grain rice might come from mutation of Chikonsorna. They were 90.92 % similar at average of three primers and their breeding programmer can use to improve rice varieties. The present study provides a baseline information to find out the origin of Twin grain rice and to develop high yielding-aromatic-twin-fine grain cocktail variety(s) through future breeding program. Twin grain rice contain lowest amount of starch and protein, 32.10% and 11.55%, respectively. In case of moisture holding it also contain lowest amount. It contains 23.27% ash where as Nagirshail contains 24.36% ash.