Senjam Pushparani, Senapati Bijoy Kumar, Chattopadhyay Arup, Dutta Subrata
Faculty of Agriculture, Department of Genetics and Plant Breeding, Bidhan Chandra Krishi Viswavidyalaya, Mohanpur 741 252, India.
J Genet. 2018 Mar;97(1):25-33.
Okra's (Abelmoschus esculentus (L.) Moench) commercial cultivation is threatened in the tropics due to high incidence of yellow vein mosaic virus (YVMV) disease. Okra geneticists across the world tried to understand the inheritance pattern of YVMV disease tolerance without much success. Therefore, the inheritance pattern of YVMV disease in okra was revisited by employing sixgenerations (P₁, P₂, F₁, F₂, BC₁ and BC₂) of four selected crosses (one tolerant × tolerant, two tolerant × susceptible and one susceptible × susceptible) using two tolerant (BCO-1 and Lal Bhendi) and two susceptible (Japanese Jhar Bhendi and PAN 2127) genotypes. Qualitative genetic analysis was done on the basis of segregation pattern of tolerant and susceptible plants in F and backcross generations of all the four crosses. It revealed that a single dominant gene along with some minor factors governed the disease tolerant trait in both the tolerant parents used. However, it was observed that genes governing disease tolerance identified in both the tolerant variety used was different. It could be concluded that the gene governing YVMV disease tolerance in okra wasgenotype specific. Further, duplicate gene action as evident from an approximate ratio of 15:1 (tolerant:susceptible) in the F population in the cross of two tolerant varieties gave a scope of increasing the tolerance level of the hybrid plants when both the tolerant genes are brought together. However, generation mean analysis revealed involvement of both additive and nonadditive effects in the inheritance of disease tolerance. Thus, the present study confirms that a complicated genetic inheritance pattern is involved in the disease tolerance against YVMV trait. The major tolerance genes could be transferred to other okra varieties, but the tolerance breaking virus strains might not allow them to achieve tolerance in stable condition. Therefore, accumulation of additional genes may be needed for a sustainable tolerance phenotype in okra.
由于黄脉花叶病毒（YVMV）病的高发病率，秋葵（Abelmoschus esculentus (L.) Moench）在热带地区的商业种植受到威胁。世界各地的秋葵遗传学家试图了解YVMV病耐受性的遗传模式，但成效不大。因此，通过使用四个选定杂交组合（一个耐病×耐病、两个耐病×感病和一个感病×感病）的六代（P₁、P₂、F₁、F₂、BC₁和BC₂），采用两个耐病基因型（BCO - 1和Lal Bhendi）和两个感病基因型（日本Jhar Bhendi和PAN 2127），重新研究了秋葵中YVMV病的遗传模式。基于所有四个杂交组合的F代和回交后代中耐病和感病植株的分离模式进行了定性遗传分析。结果表明，在所用的两个耐病亲本中，一个显性基因以及一些次要因子控制着病耐受性性状。然而，观察到在所使用的两个耐病品种中鉴定出的控制病耐受性的基因是不同的。可以得出结论，秋葵中控制YVMV病耐受性的基因是基因型特异性的。此外，在两个耐病品种杂交的F群体中，从大约15:1（耐病:感病）的比例可以明显看出存在重复基因作用，当两个耐病基因组合在一起时，为提高杂交植株的耐受性水平提供了空间。然而，世代均值分析表明，加性效应和非加性效应都参与了病耐受性的遗传。因此，本研究证实，针对YVMV性状的病耐受性涉及复杂的遗传模式。主要的耐受性基因可以转移到其他秋葵品种中，但能突破耐受性的病毒株可能不允许它们在稳定条件下实现耐受性。因此，秋葵中可能需要积累额外的基因才能获得可持续的耐受性表型。
