A High Yielding Dual Purpose Hybrid Sorghum CO 5 for Tamil Nadu

. A dual purpose sorghum hybrid TNSH 482 derived from the cross ICSA 51 x TNS 30, evolved with an objective to develop high yielding dual purpose hybrid with improved grain and stover yield besides resistant to shootfly and grain mould was released as TNAU sorghum hybrid CO 5. It is a medium tall, non-lodging and tan plant type hybrid which matures in 95 - 100 days and remains green even at maturity. The grains are creamy white in colour, borne on medium cylindrical and semi-loose ear heads. It recorded an average grain yield of 2769 Kg/ ha under rainfed which was 13.16 and 17.03 per cent increase over the checks, COH 4 and MSH 51 respectively while its mean grain yield was 4338 Kg/ha under irrigation which was 17.18 and 13.32 per cent increase over the checks, COH 4 and MSH 51 respectively. The mean stover yield was 7563 and 10548 Kg/ha under rainfed and irrigated situations respectively. The hybrid TNSH 482 is resistant to downy mildew and moderately resistant to shoot fly and grain mould disease.

Sorghum (Sorghum bicolor (L) Moench) is the fourth most important food crop in India, being the best-suited cereal for semi-arid environments. It has substantial popularity amongst farmers due to its greater adaptability and various forms of utilization like green fodder, stover and silage. It is an important staple food grain after rice and wheat for millions of poor and most food-insecure people in the semiarid tropics (SAT) in India. Sorghum also offers great potential to supplement fodder requirement of the growing dairy industry in India because of its wide adaptation, rapid growth and high green-fodder yields as well as good quality (Reddy et. al., 2010). In Tamil Nadu, it is grown in 2.38 lakh ha constituting 4.7 per cent of the total cropped area of the state. Coimbatore, Dindigul, Thiruchirapalli, Thiruppur, Karur, Salem, Dharmapuri, Madurai, and Virudhunagar districts have contributed more area to this crop accounting for 75.6 per cent of the total area under this crop in the state during 2009-10 with the productivity of 930 Kg/ha. In Tamil Nadu, sorghum is truly a dual-purpose crop where both grain and stover are highly valued outputs. Sorghum plays an important role in the fodder and feed budget of Tamil Nadu farmers who often demand dual-purpose sorghum varieties and hybrids. It is therefore of paramount importance that technological developments are extended to increase the productivity and sustainability of sorghum production. Hybrid sorghum development was initiated in Tamil Nadu Agricultural University by utilizing improved male sterile lines developed under National Agricultural Research System and ICRISAT to augment higher productivity. Hybrid sorghum breeding was oriented towards development of dual purpose and photo insensitive types with resistance to shootfly and grain mould suitable for grain and stover for growing in all seasons. This effort has resulted in the development of a high yielding dual purpose hybrid TNSH 482. Due to its high grain and fodder yields besides other desirable traits, this hybrid has been released as TNAU Hybrid Sorghum CO 5 for cultivation in Tamil Nadu.

Results and Discussion
Sorghum hybrid TNSH 482, a cross between ICSA 51 and TNS 30 is a photo -insensitive dual purpose hybrid that matures in 95 to 100 days and takes 60 days to attain 50 per cent flowering. It is a medium tall growing hybrid with mean plant height varying between 210 and 230 cm. Like many other Mean dry fodder yield of the hybrid was 12193 Kg/ha as against 11110 and 10238 Kg/ha, which was 9.75 and 19.1 per cent over the checks COH 4 and MSH 51 respectively (Table 1).    (Table 4).
Adaptability of this hybrid was assessed in the farmers' fields under Adaptive Research Trials conducted during all the three sorghum growing seasons namely kharif, rabi and summer in 158 locations spread over 21 districts of Tamil Nadu. This hybrid registered a mean grain yield of 2727 Kg/ha during kharif and summer under irrigated condition and 2588 Kg/ha during rabi season under rainfed condition with an yield increase of 10.3 and 5.9 per cent respectively over the check hybrid COH 4. The mean stover yields of the hybrid was 7743 during kharif and summer under irrigated condition and 7248 Kg/ha during rabi season under rainfed Overall performance of a hybrid and its adaptability to different agro-climatic regions of the state are the basic criterion for its identification and release as a variety in a state. Accordingly, the assessment of overall performance of the hybrid TNSH 482 under station trials, MLT and ART revealed that the hybrid registered an overall mean grain yield of 4338 Kg/ha as against 3702 and 3828 Kg/ha recorded by the check hybrids COH 4 and MSH 51 respectively with an yield increase of 17.18 and 13.32 per cent over the check hybrids respectively. The grain yield of the hybrid under rainfed was 2769 Kg/ ha and registered 13.16 and 17.03 per cent increase over the check hybrids respectively (Table 6). Sorghum is often grown for its grain apart from green and dry fodder to sustain large population of animals in Tamil Nadu. Sorghum hybrids without dry fodder yield have no value in southern peninsular India. The dry fodder yield of the hybrid had also shown improvement over the existing sorghum hybrids. The hybrid TNSH 482 registered an overall mean dry fodder yield of 10548 Kg/ ha under irrigated condition and 7563 Kg/ha under rainfed situation with an yield increase of 6.44 and 16.10 per cent over the check hybrids COH 4 and MSH 51 respectively under irrigation and 4.56 and 9.85 per cent under rainfed condition respectively (Table 7).
Sorghum production is greatly affected by a variety of insect pests and diseases. The hybrid TNS 482 was screened for their reaction to major pests and diseases along with check hybrids in addition to susceptible and resistant varieties (Table 8 &9). This hybrid showed a moderate level of resistance against shootfly and stem borer as the incidences of these pests in the hybrid were found to be moderate and even lesser than the incidence score of check hybrids viz., COH 4 and CSH 23 and far lesser than the susceptible check (DJ 6514).The incidences of head bug and midge were also found to be less as compared to check hybrids. Grain mold is a major disease wherever sorghum is grown if moist weather conditions prevail after flowering until grain maturity and before harvest. In Tamil Nadu, the incidences of grain mould is found to be predominant and there is no incidence of ergot, rust and leaf blight as seen from the disease score recorded for these diseases. Sorghum varieties with loose panicles are generally found to be resistant to grain mould (Thakur et.al, 2006). Hybrid TNSH 482 with loose panicles registered low incidence of grain mold than the check hybrids COH 4 and CSH 23 and it was categorized as moderately resistant while the incidence scores of rust and ergot in TNSH 482 were lesser than the check hybrids and was found to be resistant to these diseases.
Nutritional status of sorghum is considered to be important as the grain remains as the staple food for the millions of rural people in the state. The nutritional analysis of grain revealed (Table 10) that the hybrid TNSH 482 possessing superior nutritive qualities evidenced from the higher values scored for starch, fiber (1.73 %) and protein (8.7%) and less for tannin (63.75 mg/100g). Sorghum varieties with improved fodder parameters have a direct impact on animal productivity, a positive influence on the pricing of stover sold as animal feed, thereby contributing to income from both crop and livestock enterprises (Blummel and Rao, 2006). The fodder quality is always determined by the important traits namely, protein and dry matter digestibility. The dry fodder samples of TNSH 482 registered high value for in-vitro Dry Matter Digestibility (50 %) as compared to the check hybrids COH 4 (48.50%) and CSH 16 (49.80%). The protein content of the stover sample was 7.6 per cent.
Identification of superior dual-purpose (food and fodder) sorghum hybrids is the need of the farmer as it is the only way to meet the ever growing food, feed and fodder demands of the country (Blummel and Reddy, 2006) . The hybrid TNSH 482, owing to its superiority in grain and fodder yields than the check hybrids COH 4, MSH 51and CSH 23 under both rainfed and irrigated ecosystems and showing moderately resistant reaction to shoot fly, stem borer and grain mould and superiority in grain and fodder nutritional qualities over the checks, it was released as a new TNAU Sorghum Hybrid CO 5 for commercial cultivation in Tamil Nadu.