|KUMAR, ASHOK - International Crops Research Institute For Semi-Arid Tropics (ICRISAT) - India|
|GORTHY, SUNITA - International Crops Research Institute For Semi-Arid Tropics (ICRISAT) - India|
|SHARMA, HARI - International Crops Research Institute For Semi-Arid Tropics (ICRISAT) - India|
|SHARMA, RAJAN - International Crops Research Institute For Semi-Arid Tropics (ICRISAT) - India|
|REDDY, BELUM - International Crops Research Institute For Semi-Arid Tropics (ICRISAT) - India|
Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: 5/1/2014
Publication Date: 7/8/2014
Citation: Kumar, A.A., Gorthy, S., Sharma, H.C., Huang, Y., Sharma, R., Reddy, B.V. 2014. Understanding genetic control of biotic stress resistance in sorghum for applied breeding. In: Wang, Y-H, Upadhyaya, H.D., Kole, C., editors. Genetics, Genomics and Breeding of Sorghum. Chapter 9. Boca Raton, FL: CRC Press. p. 198-225.
Interpretive Summary: Developing host plant resistance to biotic stresses has been a challenging job for sorghum workers because of the complexities involved in variation in pest genotypes, complexity in genetic control, and difficulty in effective phenotyping for these stresses. In spite of this, sorghum improvement has come a long way from using simple classical methods to using advanced molecular tools for biotic stress resistance improvement. Efforts are underway to use new genomic tools for sorghum improvement facilitated by the availability of aligned genome sequence. The integrated genetic maps will be quite handy for the development of more efficient breeding systems in sorghum to better exploit heterosis and breed for host plant resistance to various biotic stresses. Currently the genotyping tools are increasingly available and more affordable and therefore trait phenotyping should be given high priority. The progress in developing host plant resistance to biotic stresses in the future depends upon the quality of the available phenotyping data and most appropriate genomic tools we use for establishing trait-marker associations and their deployment in breeding programs. Together, successful deployment of resistant crops contributed an important component of the integrated pest management. Recent advances in sorghum genetics, genomics and breeding have led to development of cutting-edge molecular technologies that are complementary to genetic improvement of this crop for insect pest management.
Technical Abstract: Sorghum (Sorghum bicolor (L.) Moench) improvement deals with development of new crop cultivars which are superior to existing cultivars for traits of interest like high yield, better quality, resistance to pests and diseases, and specific usability traits (Reddy et al 2011; Ashok Kumar et al 2013). Availability of genetic variability for these traits, knowledge about their heritability and genetic control, and availability of effective screening methodologies/phenotyping tools are fundamental for success of any crop improvement program. In sorghum, a large collection of germplasm is available at International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) (about 38,000 accessions) and other places with characterization information available for various morphological, agronomic, and adaptive traits. Inheritance of major traits is well studied and phenotyping techniques are developed for efficient selection/screening for major traits of interest. There is continuous exchange of material and information across different research groups. As a result, a large number of sorghum cultivars were developed and commercialized across the world for traits of interest. For example, during the period of 1976 to 2010, a total of 242 sorghum cultivars were released in 44 countries using the ICRISAT-bred sorghum material by private and public sector organizations (Kumar et al 2011). The list is quite exhaustive if we consider cultivars developed by other centers in all sorghum growing countries. Focused sorghum improvement programs backed by germplasm sources, information on heritability and gene action for traits of interest, screening techniques, established selection procedures, massive adaptive trials in partners' locations and above all, collaborative research, contributed for the large scale development and commercialization of improved cultivars in some of the agro eco systems. This chapter deals with recent developments with regard to sorghum adaptation to different production systems, major biotic stresses affecting sorghum production, understanding genetic control of biotic stress resistance, screening techniques developed, and progress made in cultivar development using this knowledge.