PDF(Pubmed)
Abstract：
Water scarcity is a crucial environmental stress that constrains rice growth and production. Thus, breeding for developing high-yielding and drought-tolerant rice genotypes is decisive in sustaining rice production and ensuring global food security, particularly under stress conditions. To this end, this study was conducted to evaluate the effects of water deficit on 31 genotypes of rice (seven lines, viz., Puebla, Hispagran, IET1444, WAB1573, Giza177, Sakha101, and Sakha105, and three testers, viz., Sakha106, Sakha107, and Sakha108) and their 21 crosses produced by line × tester mating design under normal and water deficit conditions; this was to estimate the combining ability, heterosis, and gene action for some traits of physiological, biochemical, and yield components. This study was performed during the summer seasons of 2017 and 2018. The results showed that water deficit significantly decreased relative water content, total chlorophyll content, grain yield, and several yield attributes. However, osmolyte (proline) content and antioxidant enzyme activities (CAT and APX) were significantly increased compared with the control condition. Significant mean squares were recorded for the genotypes and their partitions under control and stress conditions, except for total chlorophyll under normal irrigation. Significant differences were also detected among the lines, testers, and line × tester for all the studied traits under both irrigation conditions. The value of the σ²GCA variance was less than the value of the σ²SCA variance for all the studied traits. In addition, the dominance genetic variance (σ2D) was greater than the additive genetic variance (σ2A) in controlling the inheritance of all the studied traits under both irrigation conditions; this reveals that the non-additive gene effects played a significant role in the genetic expression of the studied traits. The two parental genotypes (Puebla and Hispagran) were identified as good combiners for most physiological and biochemical traits, earliness, shortness, grain yield, and 1,000-grains weight traits. Additionally, the cross combinations Puebla × Sakha107, Hispagran × Sakha108, and Giza177 × Sakha107 were the most promising. These results demonstrated the substantial and desirable specific combining ability effects on all the studied traits, which suggested that it could be considered for use in rice hybrid breeding programs.
摘要：
水资源短缺是制约水稻生长和生产的关键环境压力。因此，培育高产耐旱水稻基因型对维持水稻产量和确保全球粮食安全具有决定性作用,特别是在压力条件下。为此,本研究旨在评估水分亏缺对31个基因型水稻(7个品系，viz.,普埃布拉,Hispagran,IET1444，WAB1573，Giza177，Sakha101和Sakha105，以及三个测试人员，viz.,Sakha106，Sakha107和Sakha108）及其在正常和缺水条件下通过线×测试仪配合设计产生的21个杂交；这是为了估计结合能力，杂种优势，和一些生理特征的基因作用，生物化学，并产生组件。这项研究是在2017年和2018年的夏季进行的。结果表明,水分亏缺显著降低了相对含水量,总叶绿素含量，粮食产量，和几个产量属性。然而,与对照条件相比，渗透压（脯氨酸）含量和抗氧化酶活性（CAT和APX）显着增加。在控制和胁迫条件下，记录了基因型及其分区的显着均方，除了正常灌溉下的总叶绿素。在品系之间也检测到显着差异，测试人员,在两种灌溉条件下，所有研究性状的线×测试仪。对于所有研究的性状，σ²GCA方差的值小于σ²SCA方差的值。此外,在两种灌溉条件下控制所有研究性状的遗传时，优势遗传变异（σ2D）大于加性遗传变异（σ2A）；这表明非加性基因效应在研究性状的遗传表达中起着重要作用。两个亲本基因型（Puebla和Hispagran）被确定为大多数生理和生化性状的良好组合物。早熟,矮小，粮食产量，和1000粒的体重特征。此外,Puebla×Sakha107，Hispagran×Sakha108和Giza177×Sakha107的杂交组合最有希望。这些结果证明了对所有研究性状的实质性和理想的特定结合能力效应，这表明它可以考虑用于水稻杂交育种计划。
