Sorghum Genetic Resources, Cytogenetics, and Improvement

Sorghum (Sorghum bicolor (L.) Moench) is the world's fourth major cereal crop in terms of production, and fifth in acreage following wheat, rice, maize, and barley. Sorghum is mostly grown in the semiarid tropics (SAT) of the world as a subsistence dry-land crop by resource-limited farmers under traditional management conditions, thereby recording low productivity compared to the U.S. and Mexico. India grows the largest acreage of sorghum in the world, followed by Nigeria and Sudan, and produces the second largest tonnage after the U.S., with Nigeria being the third largest producer. In most of the regions of India, it is cultivated both as a rainy- and postrainy-season crop

Genetic analysis of traits contributing to stalk sugar yield in sorghum

Sweet sorghum (Sorghum bicolor (L.) Moench) is a potential raw material for production of ethanol that on blending in petrol is expected to meet the energy demand and address the environmental issues. Well-developed hybrid technology will make the crop remunerative to the farmers. Hence, gene action and best combining female and male parents for sugar yield in sweet sorghum (Sorghum bicolor (L.) Moench) and the association of sugar yield with other agronomic traits was studied in 171 hybrids developed by crossing 19 female parents with nine male parents in line × tester design and evaluated during both rainy and postrainy seasons of 2006. The significant differences between the seasons for all the traits suggested that these traits are greatly influenced by the environment. The lines (female parents) ICSA 38, ICSA 479, ICSA 702, ICSA 675 and ICSA 474 and the restorers (male parents), SSV 74 and SSV 84 combined well for sugar yield during rainy season and the lines, ICSA 702, ICSA 38 and ICSA 474 and the restorers, ICSV 93046, SPV 1411 and ICSV 700 combined well during postrainy season. The magnitude of SCA variance was higher suggesting the importance of non-additive gene action in inheritance of all the traits though both additive and dominant genes controlled overall sugar yield during both the seasons. Hence, selection in early generation would be ineffective and recurrent selection with periodic intercrossing is advocated. However, breeding good combining restorer parents can fetch high sugar yield in postrainy season. There is an indication of existence of transgressive segregation for sugar yield that can be exploited. The sugar yield was weak though significantly correlated with high brix and poor grain yield during both the seasons requiring extensive crossing to improve these traits simultaneously. Keeping in view mean performance, SCA effects and heterobeltiosis, the hybrids, ICSA 474 × SSV 84, ICSA 24001 × ICSR 93046 and ICSA 474 × SPV 422 were identified promising for rainy season and the hybrids ICSA 24001 × SPV 1411 and ICSA 511 × ICSV 93046 were identified for postrainy season

Combining ability for grain mold resistance in sorghum (Sorghum bicolor (L.) Moench)

In all sorghum (Sorghum bicolor (L.) Moench) production systems, grain molds can reduce the yield and quality of short duration cultivars if they mature in wet and humid weather. This investigation was taken up to find out combining ability for grain mold resistance under 4 environmental conditions by studying 168 hybrids and their parents along with checks. The pooled analysis of variance for combining ability revealed significant differences due to environments, parents, hybrids and various interactions indicating the existence of wide variability in the material under study. The ratios of additive to dominance variances revealed that additive gene action was predominant for inheritance of grain mold resistance (Panicle Grain Mold Rating - PGMR). Among the parents, two A-lines ICSA 369 and ICSA 370 and six testers viz., IS 41675, ICSR 91011, ICSR 89058, PVK 801, GD 65028, GD 65055 in all the 4 environments were identified as a good general combiners for grain mold resistance. These parents can be utilized for the development of grain mold resistant hybrids

Genetic improvement of sorghum in the semi-arid tropics

Sorghum [Sorghum bicolor (L.) Moench] – a major cereal of the world after wheat, rice, maize and barley, is a staple food for millions of the poorest and most foodinsecure people in the Semi-Arid Tropics (SAT) of Africa and Asia. Being a C4 species with higher photosynthetic ability, and greater nitrogen and water-use effi ciency, sorghum is genetically suited to hot and dry agro-ecologies where it is diffi cult to grow other food crops. These are also the areas subjected to frequent droughts. In many of these agro-ecologies, sorghum is truly a dual-purpose crop; both grain and stover are highly valued products. In Africa, sorghum is predominantly grown for food purposes, while in USA, Australia, China, etc, it is grown for livestock feed and animal fodder purposes. Unlike in other parts of the world, sorghum is grown both in rainy and postrainy seasons in India. While the rainy season sorghum grain is used both for human consumption and livestock feed, postrainy season produce is used primarily for human consumption in India. Thus sorghum is the key for the sustenance of human and livestock populations in SAT areas of the world

Designing a sorghum genetic improvement program

For ages farmers have exercised selection through saving and carrying forward the grain from healthy plants as seed for sowing the next crop. Plant breeders further augmented/enhanced the crop productivity, thus mediating directed evolution. The art of plant breeding lies in the breeder’s skills in observing plants with unique economic, environmental, nutritional and aesthetic characteristics. In this article, we briefl y describe various factors that need to be considered in launching a crop improvement program with emphasis on sorghum

Recent Advances in Sorghum Improvement Research at ICRISAT

Sorghum (Sorghum bicolor (L.) Moench) is one of the most important cereal crops widely grown for food, feed, fodder, forage and fuel in the semi-arid tropics of Asia, Africa, the Americas and Australia. In spite of rapid decreases in the area of sorghum in Asia, the production level has been maintained owing to the adoption of high yielding hybrids. Though impressive progress has been made in improving the sorghum cultivars for resistance to biotic and abiotic challenges, grain mold, shoot fly and terminal drought haunt sorghum growers across Asia. The International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) and national programs in India, China and Thailand are working on genetic enhancement of sorghum for high yield, grain mold and shortly resistance. In addition, the trait focus at ICRISAT includes post rainy season adaptation encompassing terminal drought tolerance, genetic enhancement for high Fe and Zn contents in grain and sweet stalk traits for ethanol and animal feed production. Genetic and cytoplasmic diversification of hybrid parents for key traits is critical for sustaining the productivity across different production systems. The grain and stover quality need special attention in sorghum improvement research to enhance the market value of sorghum. A brief description is provided of the progress made at ICRISAT in partnership with national programs in recent years in these areas of sorghum genetic enhancement

M 35-1 derived sorghum varieties for cultivation during the postrainy season

The variety M 35-1 dominates the postrainy season sorghum areas in India. Several varieties were developed at ICRISAT incorporating genes from M 35-1.Participatory plant breeding was carried out to select for farmer-preferred traits. The resultant 23 varieties were tested in comparison to M 35-1 in randomized complete block design for two consecutive years. Two varieties, SP 18008 and SP 18034, were promising and significantly outyielded the check M 35-1. SP 18008 and SP 18034 had a plant height of 2.7 m and 2.0 m, grain yield of 620 and 610 g m-2, flowering time 76 to 82 days and 100-grainweight of 3.9 to 4.0 g

Development of male-sterile lines in sorghum

Sorghum [Sorghum bicolor (L.) Moench] is the fi fth important cereal crop in the world after wheat, rice, maize and barley. Of late, it has emerged as ‘fuel’ crop in addition to its food, feed and fodder utilities. Sorghum is predominantly a selfpollinated crop and development of new ‘varieties’ is a natural option for crop improvement. However, there is 5 to 15% outcrossing in sorghum depending upon the wind direction, nature of genotype, and humidity (House 1985), which makes it amenable for use in population improvement and hybrid development to exploit the heterosis. Discovery of genetic male sterility (GMS) and cytoplasmic-nuclear male sterility (CMS) facilitated the application of recurrent selection procedures and hybrid cultivar development methods, respectively, in sorghum improvement. In this article, male-sterile line development using CMS in sorghum is described