TNAU Sorghum CO 30 - A High Yielding Dual Purpose Variety for Tamil Nadu

A dual purpose sorghum culture TNS 598 (hybrid derivative of the cross APK 1 x TNS 291) developed with an objective of combining high grain and fodder yield was released as TNAU sorghum CO 30. It is a tall growing non-lodging tan plant type variety, matures in 100 - 105 days and remains green even at maturity. The grains are creamy white in colour, borne on medium cylindrical semi-compact ear heads. It recorded an average grain yield of 2805 Kg/ha under rain-fed with 20.7 per cent and 19.3 per cent increase over CO(S) 28 and APK 1 respectively while its mean grain yield was 3364 Kg/ha under irrigation which is 19.2 per cent and 23.7 per cent increase over CO(S) 28 and APK 1 respectively. The mean stover yield was 6988 Kg/ha and 9292 Kg/ha under rain fed and irrigated situation respectively. The culture TNS 598 is resistant to downy mildew and moderately resistant to shoot fly, stem borer and grain mould disease.

Sorghum (Sorghum bicolor (L) Moench) ranks fifth in worldwide economic importance among cereal crops with an annual production of 60 million tons. Besides being an important food, feed and forage crop, sorghum also provides raw material for the production of starch, fiber, dextrose syrup, biofuels, alcohol, and other products. More than half of the world's sorghum is grown in semi-arid tropics of India and Africa, where it is a staple food for millions of poor people (Reddy et al., 2010). In Tamil Nadu, it is grown in 2.84 lakhs ha constituting 4.9% of the total cropped area of the state.

Dindigul,
Coimbatore, Dharmapuri, Theni, Namakkal, Thiruchirapalli, Vellore, Perambalur and Madurai districts have contributed more to this crop accounting for 75.4% of the total area under this crop in the state during 2007-08 with the productivity of 874 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 sorghums. Therefore, it can play a vital role for the uplift of socio-economic status of the farmers through development of high yielding dual purpose varieties with reasonable amount of grain and dry fodder during winter season for the livestock (Blummel and Reddy, 2006). It is therefore of paramount importance that technological developments are extended to increase the productivity and sustainability of sorghum production. Sorghum breeding has to be oriented towards development of dual purpose photo insensitive types suitable for growing in all seasons with shorter duration and tall stature. Sorghum breeding programme initiated at Tamil Nadu Agricultural University has resulted in the development of a high yielding dual purpose culture TNS 598. Due to its high grain and fodder yields besides other desirable traits, the culture has been released as TNAU Sorghum CO30 for cultivation in Tamil Nadu.

Materials and Methods
Sorghum culture TNS 598 was evolved through hybridization followed by pedigree method of selection by involving a high yielding drought resistant sorghum variety APK 1 as female parent and a culture identified for resistance to shoot fly and stem borer viz., TNS 291 as male parent.

Results and Discussion
Sorghum culture TNS 598, a cross derivative of APK1 X TNS 291 is a photo-insensitive dual purpose culture matures in 100 to 105 days and takes 60 to 65 days to attain 50% flowering. It is a tall growing culture with mean plant height varying between 210 and 230 cm. Like many other improved sorghum varieties, it has a plant with tan colour foliage and remains green even at maturity. The grains are medium bold (thousand grain weight: 28.3g) and creamy white in colour, borne on medium cylindrical semi-compact ear heads.
The results of the station trials conducted with sorghum culture TNS 598 during kharif and summer seasons under irrigated condition revealed that the culture TNS 598 registered a mean grain yield of 3998 kg/ha as against 3317 and 3113 kg/ha by the check varieties CO (S) 28 and APK1 respectively. An increase in grain yield was found in this culture to the tune of 20.5 and 28.4 per cent over the check varieties CO (S) 28 and APK 1 respectively. Mean dry fodder yield of the culture was 11523 kg/ha as against 10734 and 10357 kg/ha, which is 7.4 per cent and 11.3 per cent respectively (Table 1).
This recorded a grain yield of 3503 kg/ha under Multi Location Trials conducted during kharif and summer seasons under sandy loam soil types under irrigated condition, which were 20.8 and 29.4 per cent increase over CO(S) 28 and APK 1 respectively. It also registered a dry fodder yield of 10297 kg/ha, while the checks CO(S) 28 and APK 1 recorded 9224 and 8867 kg/ha respectively ( Table  2).The culture TNS 598 was also tested under rainfed vertisol at research stations located in southern districts of the state known for the traditional grain and fodder sorghum cultivation. This 115 culture recorded a mean grain yield of 3175 kg/ha under rainfed vertisol with an yield increase of 30.8 and 27.7 per cent over CO(S) 28 and APK 1 respectively (Table 3). These results indicated the superior performance of the culture both under irrigation and rainfed and in different soil types as compared to the check varieties. Being a dual purpose culture,TNS 598 was evaluated at national level in the name of SPV 1816 under All India Co-ordinated Sorghum Improvement Project's dual sorghum breeding trial conducted during kharif, 2007. This culture registered a grain yield of 5044 kg/ha, which was 13.0 and 13.9 per cent increase over the national checks viz., SPV 462 and CSV 15 respectively. This culture had also produced a dry fodder yield of 14031 kg/ha, while the checks SPV 462 and CSV 15 recorded 13490 kg/ha and 13694 kg/ha respectively (Table 4).
Adaptability of this culture was assessed in the farmers' field under Adaptive Research Trials conducted during all the three sorghum growing seasons namely kharif, rabi and summer in 150  (Table 5).
Overall performance of a culture 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 culture TNS 598 under stations, MLT and ART revealed that the culture registered an overall mean grain yield of 3364 kg/ha as against 2823 kg/ha and 2719 kg/ha recorded by the check varieties CO(S) 28 and APK 1 respectively with an yield increase of 19.2 and 23.7 per cent over the check verities respectively. The grain yield of the culture under rainfed was 2805 kg/ ha and registered 20.7 and 19.3 per cent increase over the check varieties (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 varieties without dry fodder yield have no value in southern peninsular India. The dry fodder yield of the culture had also with an yield increase of 11.0 and 13.0 per cent over the check varieties CO(S) 28 and APK 1 respectively under irrigation and 11.1 and 11.2 per cent under rainfed condition (Table 7). Sorghum production is greatly affected by a variety of insect pests and diseases. The culture TNS 598 was screened for their reaction to major pests and diseases along with check varieties in addition to susceptible and resistant varieties (Table 8  &9). This culture showed a moderate level of resistance against shootfly and stem borer as the incidence of these pests in the culture were found to be moderate and even lesser than the incidence score of check varieties viz., CO (28) and CSV 15 and far lesser than the susceptible check (DJ 6514).The incidence of head bug and midge was also found to be less as compared to check varieties. In Tamil Nadu, the incidence of grain mould and rust are found to be predominant and there was no incidence of ergot and leaf blight as seen from the disease score recorded for these diseases. The level of incidence of grain mold in TNS 598 was lesser than the check variety CO(S) 28 and it was 117 categorized as moderately resistant while the incidence score of rust in TNS 598 and the check CO(S) 28 was similar and moderately low hence both were found to be moderately resistant to rust disease.
Nutritional status of sorghum is considered to be important as the grain remain as the staple food for the millions of rural people in the state. The nutritional analysis of grain revealed the culture TNS 598 possessing superior nutritive qualities evidenced from the higher values scored for starch, fiber, protein and less tannin. 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). Furthermore, because the feed part of the crop plant is produced using the same resources (land, labour, capital, water) as the grain, there is a reduction in the pressure for potentially environmentally demanding Identification of superior dual-purpose food and fodder sorghum varieties 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. By evolving superior dual-purpose sorghum varieties like TNS 598 suited to Tamil Nadu's millions of smallholder farmers, the crop improvement research in sorghum has been path-breaking in demonstrating that traits for grain yield, grain quality, stover quality and quantity can be incorporated into a single variety. The culture TNS 598 owing to its superiority in grain and fodder yields than the check varieties, CO(S) 28 and APK 1 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 check CO (S) 28, it was released as a new sorghum variety TNAU Sorghum CO 30 for commercial cultivation in Tamil Nadu.