特大粒甘蓝型油菜籽粒和角果发育形态特征

为进一步了解特大粒甘蓝型油菜种质DL01的大粒机理，以普通籽粒H8为对照，田间调查并比较分析它们的生育期、主花序角果和籽粒在形态、重量、灌浆速率和相对含水量等特征及变化。结果表明，特大籽粒DL01的平均全生育期为207d，比H8长17d，尤其是灌浆期长12d以上；在开花当天，DL01的花梗直径、子房的长度和宽度及重量分别是H8的1.30、1.21、1.39、1.46倍；其最大角果皮光合面积和角果鲜重分别是H8的2.2和3.0倍；单荚胚珠数二者相当，但DL01的着粒数比H8少，最大差异为64%；DL01最大籽粒鲜重（百粒重1.20g）、干重、体积和灌浆速率均是H8的2倍；在含水量方面，在荚角成熟前DL01的果皮含水量比H8略高（3%～5%），但H8荚果高含水量（〉75%）期只能维持68d，而DL01荚果高含水量（〉80%）期可维持80d；H8籽粒鲜重在47d时达到最高，其含水量为52%，DL01籽粒鲜重在62d时达到最高，其含水量为50%。因此结论是，DL01大粒源自大子房、粗花梗、大的角果皮表面积、低着粒数、高的果皮与籽粒含水量并且灌浆持续时间较长。

Molecular Dissection of Relationship Between Seedling Characteristics and Seed Size in Rice

Seedling characteristics such as leaf emergency, chlorophyll content, and height are important for early growth and also associated with seed size. Quantitative trait loci (QTLs) for rice (Oryza sativa L.) seedling characteristics (leaf length, chlorophyll content, seedling height) and seed size were identified with an attempt to explore the relationship between seedling characteristics and seed size, using a recombinant inbred population derived from a cross between Zhenshan 97A and Minghui 63. Two, one, five, four, four, and nine QTLs were detected for chlorophyll a content, total chlorophyll, length of the second seedling leaf, length of the third seedling leaf, seedling height, and seed size, respectively. The results indicated that four QTLs for seed size and four QTLs for seedling characteristics shared several similar regions (G359-RG532, C567-RG236, RZ403-R19, C371-C405a), respectively, suggesting a close association between seedling characteristics and seed size. Several chromosomal regions influencing seed size, however, had no effects on seedling characteristics, suggesting that it was possible to improve seedling vigor without increasing grain size.