裸燕麦小花形态表型鉴定方法与落粒的形态学机制研究

落粒性是影响裸燕麦产量与品质的关键性状。本研究对228份具有代表性的裸燕麦材料的落粒性及小花的形态等15个性状进行田间多点鉴定，并建立了裸燕麦小花形态表型的鉴定方法。结果表明，15个性状在3个试验地点之间均表现出了不同程度的差异；裸燕麦的落粒性同内稃宽度(相关系数r=-0.36)、内稃面积(r=-0.30)、外稃宽度(r=-0.26)等9个性状呈显著或极显著负相关，与种子同内稃宽度的比值(r=0.37)及种子同外稃宽度的比值(r=0.20)呈极显著正相关，说明内外稃的宽度影响小花中种子的包裹程度，外稃厚度影响小花抵抗外力的能力，从而影响裸燕麦的落粒性。K-means聚类分析将参试材料分为两大类，Ⅰ类占整个群体的48%(110个),内稃和外稃整体上更加窄小，落粒性较高；Ⅱ类占群体的52%(118个),内稃和外稃整体上更加宽大，落粒性较低。对3个地点参试材料落粒性的密度分布进行了分析，提出了裸燕麦落粒性评价的等级划分标准：0～0.03为低落粒性，0.03～0.08为中落粒性，0.08～0.16为较高落粒性，0.16～0.23为高落粒性，大于0.23为极高落粒性。

Methods for Floret Morphology Identification and Morphological Mechanisms of Seed Shattering in Avena nuda

Seed shattering is a key factor that affects the yield and quality of naked oat (Avena nuda). In this study, 228 naked oat materials were used for the identification of 15 traits including seed shattering and floret morphological traits. Methods for floret morphology identification were established. Results showed varying degrees of differences among the 15 traits, in the three trial locations. Nine traits including palea width (r=-0.36), palea area (r=-0.30) and lemma width (r=-0.26) showed significant or extremely significantly negative correlations to seed shattering. Seed-palea width ratio (0.37) and seed-lemma width ratio (0.2) showed extremely significant correlation to seed shattering. Conclusions can be drawn that the width and area of paleas and lemmas affects seed shattering by altering the degree of encapsulation of the seeds, and the overall thickness of lemmas affects seed shattering by regulations of resistance to external forces. The population could be divided into two clusters according to K-means analysis, with cluster one presenting smaller paleas and lemmas, but higher seed shattering rate, and cluster two presenting larger paleas and lemmas, but lower seed shattering rate. The percentage ratio of the two clusters were 48% (110 materials) and 52% (118 materials), respectively. Furthermore, the density plots of seed shattering rate of the population at the three locations were analyzed, and the grading standard for the evaluation of seed shattering rate in naked oat was proposed accordingly, with the shattering rate of 0-0.03, 0.03-0.08, 0.08-0.16, 0.16-0.23 and over 0.23 being low shattering, medium shattering, relatively high shattering, high shattering, and extremely high shattering, respectively.