Sunilkumar V P, Krishna Hari, Devate Narayana Bhat, Manjunath Karthik Kumar, Chauhan Divya, Singh Shweta, Sinha Nivedita, Singh Jang Bahadur, Prakasha T L, Pal Dharam, Sivasamy M, Jain Neelu, Singh G P, Singh P K
Division of Genetics, Icar- Indian Agricultural Research Institute, New Delhi, India.
ICAR-Indian Institute of Wheat and Barley Research, Karnal, India.
Front Plant Sci. 2022 Oct 24;13:1035016. doi: 10.3389/fpls.2022.1035016. eCollection 2022.
There is a significant yield reduction in the wheat crop as a result of different biotic and abiotic stresses, and changing climate, among them moisture deficit stress and leaf rust are the major ones affecting wheat worldwide. HD3086 is a high-yielding wheat variety that has been released for commercial cultivation under timely sown irrigated conditions in the Indo-Gangetic plains of India. Variety HD3086 provides a good, stable yield, and it is the choice of millions of farmers in India. It becomes susceptible to the most prevalent pathotypes 77-5 and 77-9 of Puccinia triticina (causing leaf rust) in the production environment and its potential yield cannot be realized under moisture deficit stress. The present study demonstrates the use of a marker-assisted back cross breeding approach to the successful transfer of leaf rust resistance gene Lr24 and QTLs linked to moisture deficit stress tolerance in the background of HD3086. The genotype HI1500 was used as a donor parent that possesses leaf rust-resistant gene Lr24, which confers resistance against the major pathotypes found in the production environment. It possesses inbuilt tolerance under abiotic stresses with superior quality traits. Foreground selection for gene Lr24 and moisture deficit stress tolerance QTLs linked to Canopy temperature (CT), Normal Differential Vegetation Index (NDVI) and Thousand Kernel Weight (TKW) in different generations of the backcrossing and selection. In BC2F2, foreground selection was carried out to identify homozygous lines based on the linked markers and were advanced following pedigree based phenotypic selection. The selected lines were evaluated against P. triticina pathotypes 77-5 and 77-9 under controlled conditions. Recurrent parent recovery of the selected lines ranged from 78-94%. The identified lines were evaluated for their tolerance to moisture stress under field conditions and their resistance to rust under artificial epiphytotic conditions for two years. In BC2F5 generation, eight positive lines for marker alleles were selected which showed resistance to leaf rust and recorded an improvement in component traits of moisture deficit stress tolerance such as CT, NDVI, TKW and yield compared to the recurrent parent HD3086. The derived line is named HD3471 and is nominated for national trials for testing and further release for commercial cultivation.
由于不同的生物和非生物胁迫以及气候变化，小麦作物产量显著下降，其中水分亏缺胁迫和叶锈病是影响全球小麦的主要因素。HD3086是一个高产小麦品种，已在印度恒河平原适时播种灌溉条件下进行商业化种植。HD3086品种产量良好且稳定，是印度数百万农民的选择。在生产环境中，它对小麦叶锈菌最普遍的致病型77-5和77-9敏感（导致叶锈病），在水分亏缺胁迫下其潜在产量无法实现。本研究展示了使用标记辅助回交育种方法，在HD3086背景下成功转移叶锈病抗性基因Lr24和与水分亏缺胁迫耐受性相关的QTL。基因型HI1500用作供体亲本，其具有叶锈病抗性基因Lr24，可抵抗生产环境中发现的主要致病型。它在非生物胁迫下具有内在耐受性，并具有优良的品质性状。在回交和选择的不同世代中，对与冠层温度（CT）、归一化植被指数（NDVI）和千粒重（TKW）相关的基因Lr24和水分亏缺胁迫耐受性QTL进行前景选择。在BC2F2中，基于连锁标记进行前景选择以鉴定纯合系，并根据系谱进行表型选择进一步推进。所选品系在受控条件下针对小麦叶锈菌致病型77-5和77-9进行评估。所选品系的轮回亲本恢复率在78%-94%之间。对鉴定出的品系在田间条件下的水分胁迫耐受性以及在人工流行条件下的锈病抗性进行了两年评估。在BC2F5代中，选择了八个标记等位基因阳性品系，这些品系对叶锈病表现出抗性，并且与轮回亲本HD3086相比，在水分亏缺胁迫耐受性的组成性状如CT、NDVI、TKW和产量方面有所改善。衍生品系命名为HD3471，并被提名进行国家试验以进行测试并进一步发布用于商业化种植。
