利用RAPD技术研究弱秋眠性紫花苜蓿遗传多样性

Genetic Diversity Analysis of Weak-fall Dormancy Alfalfa

在4 2个供试品种中选出生长势良好的半秋眠、不秋眠紫花苜蓿(MedicagosativaL )品种13份,用RAPD技术对其遗传多样性进行分析。结果表明,30个随机引物均能扩增出清晰的条带,数目在1～14条之间。其中12条引物占所用引物的4 0 % ,在13份材料中共产生分子量不同的12 6个RAPD标记,其中多态性条带116条,占92 0 6 %。说明半秋眠、不秋眠紫花苜蓿的多态性远高于中国紫花苜蓿地方品种(70 6 8% ) ,是一类具有较高遗传多样性的苜蓿基因类群。弱秋眠性苜蓿品种具有丰富的遗传基础,其遗传保守性可能较差,或具有更广泛的适应潜力和开发价值。遗传距离分析结果表明,弱秋眠性紫花苜蓿在遗传上既具有一定的一致性,又具有各自独立的遗传性,遗传背景丰富。本试验结果为云南省今后进一步引进、利用优质弱秋眠性紫花苜蓿种质资源,丰富种质资源信息库,培育新良种提供了分子生物学依据。

Alfalfa (Medicago sativa L.) is plante d mainly in North China. Most of researches on it also focus on those accession s with strong-fall dormancy. Studies have shown that fall dormancy of alfalfa and lower soil's pH are main obstacles to prevent alfalfa extension from north t o south. On conditions that sunlight is not enough but temperature is adaptive to plant growth, the accessions with weak-fall dormancy can give a higher yiel d yearly, while those with non-fall dormancy can improve their yield seasonall y. With the increase of K value (wet-degree) and decrease of latitude, fa ll dormant degrees of adaptive alfalfa species will be increase (while the fall dormant trait of alfalfa weaked). Yunnan Province is located in the subtropical region of South China. Climate here is temperate with a long frost-free perio d and plenty of rain. Theoretically, alfalfa with weak-fall dormancy should h ave a promising adaptability. Thirteen alfalfa cultivars were selected from forty-two promising cult iva rs with semi-fall dormancy and non-dormancy, they can grow very well in natur al climate of Kunming. We employed RAPD to do some analyses of the genetic poly morphism of these cultivars. The results showed that the amplificatio n products were obtained using 30 random primers, showing 1-14 distinguishable bands. Among them, 12 primers were need to thirteen samples, which were 40% o f those employed, producing 126 RAPD markers with different molecular weights, among which there were 116 polymorphic bands, accunted for 92.06% of the total . Cultivars with semi-dormancy and non-dormancy had high genetic polymorphism , showing much higher polymorphism than native cultivars (70.68%). The cultiv ars with weak-fall dormancy were with rich genetic foundation. Their adaptabil ity and merits were discussed. The result of genetic distance analysis showed t hat alfalfa with weak-fall dormancy has certain coincident and independent as w ell as rich genetic backgrounds. The studies offer some molecular biological fo undation for aiding to introduce and utilize of alfalfa accessions with w eak-fall dormancy and high quality in Yunnan Province, enrich genetic informat ion database and promote alfalfa breeding.