高温伏旱下籼粳型水稻不育系的开花习性

目的]研究高温伏旱与籼粳型水稻不育系开花习性的关系,并鉴定高温伏旱条件下具有良好开花习性的籼粳型水稻不育系,为新选系的应用和地方种质的进一步改良提供理论依据.方法]以5个偏粳型和5个偏籼型的籼粳型水稻不育系材料为研究对象,通过大田分期播种,使各参试材料开花期遭遇自然高温伏旱,通过调查单穗开花花时动态、单穗和单株开花历期及柱头外露率等指标对参试材料进行综合评价.结果]参试材料间开花习性差异明显;在高温伏旱条件下,材料类型是导致开花习性差异的主要因子;其中6466A、6474A、805A和650A等4个不育系具有开花高峰期较早、单穗和单株开花历期较长、柱头外露率较高、柱头生活力高等优点.6466A开花高峰期集中在10:31~12:00,较G46A提前1.5 h;6474A的柱头外露率较高,达78.16%;650A的单株开花历期最长,达17.2 d;805A的柱头生活力较高,且可保持时间较长.结论]不育系6466A、6474A、805A和650A在高温伏旱条件下表现出较好的开花习性,可作为高温伏旱下育种的选育亲本,或在种质资源改良中加以利用.

Flowering habit of indica-japonica cytoplasmic male sterile lines under high temperature and summer drought

Objective]The relationship between high temperature,summer drought and flowering habits of indica-ja-ponica cytoplasmic male sterile(CMS)lines was studied,and CMS lines of good flowering habits under high temperature and summer drought were screened in order to provide theoretical basis for application of new sterile lines and improve-ment of local germplasms.Method]Five japonica-cline and five indica-cline male sterile lines were sown in field at di-fferent times to make sure that all tested lines underwent high temperature and summer drought during flowering stage. These tested lines were comprehensively evaluated based on flowering dynamics of single panicle,anthesis duration of single panicle and whole plant,and exerted stigma rate.Result]The results indicated significant differences with respect to flowering habits among tested lines. Under high temperature and summer drought conditions,the differences in flowering habit were mainly due to variety type. CMS lines 6466A,6474A,805A and 650A had advantages in earlier flowering peak,longer anthesis duration of single panicle and whole plant,and higher exerted stigma rate and stigma vitality. The flowering peak of 6466A was during 10:31-12:00,1.5 h earlier than that of G46A. The exerted stigma rate of 6474A was high,reaching 78.16%. 650A had the longest anthesis duration of whole plant which was up to 17.2 d. 805A had high stigma vitality and long lasting time of stigma.Conclusion]CMS lines 6466A ,6474A ,805A and 650A have good flowering habits under high temperature and summer drought conditions. These lines can be used as parents for breeding under high temperature and summer drought conditions and applied in improvement of germplasm resources.