Potential general combiners for grain mold resistance in kharif-sorghum

Introduction

Sorghum [Sorghum bicolor (L.) Moench] is one of the major millets grown in India, belonging to the family Poaceae. It functions as a versatile crop for nourishment, livestock feed, and energy, and is essential for ensuring food security in rural areas. Grain mold poses one of the significant biological challenges to enhancing the quality and production of kharif sorghum. Mold damage can manifest in various forms, including discolored grains, reduced grain filling and size, lower seed germination rates, the presence of mycotoxins, diminished density and test weight, changes in grain composition, poor storability, decreased nutritional value, lower consumer acceptance, and a reduced market price. Various management approaches, including avoidance, the application of fungicides, chemical interventions, and the use of resistant varieties, were implemented to manage grain mold infections. Among them avoidance or chemical control on farmer's field is impracticable. In contrast, the use of resistant varieties is appeared to be cost-effective and efficient method to control grain mold (Mofokeng et al., 2017, Das et al., 2022) [4,1] . The objective of the present study, is to identify parents that exhibit good combining ability for traits related to resistance to grain mold.

Materials and Methods

The research experiment was conducted on the field of Sorghum Research Unit, Dr. P.D.K.V., Akola. The experimental material consisted of ten parents viz., CSV 27, CSV 34, PDKV Kalyani, RMP-42, AKMS 30B, AKMS 14B, GMN-16-3, AKGMR 117, AKGMR 118, B 58586 and 45 F 1 crosses. These 45 F 1 crosses were developed by crossing ten diverse parents in 10 x 10 half diallel mating design. The experiment was conducted in Randomized block design with three replications. The observations were recorded on five competitive plants for field grade mold rating (FGMR) [1 to 9 scale], threshed grade mold rating (TGMR) [1 to 9 scale], grain hardness, grain density, electrical conductivity of grain leachates, germination percentage, glume coverage percentage, water absorption capacity, fungal load of Fusarium spp., fungal load of Curvularia spp. fungal load of other mold spp. and grain yield per plant. The analysis of combining ability was performed using the mean values across replications for the traits, following method II model 1 as described by Griffing in 1956 [2] .

Results and Discussion

An analysis of combining ability was conducted for all 12 traits of the F1 crosses and is shown in Table 1. The variance existing due to treatments was further partitioned using appropriate expectations of the observed mean squares into components of variations attributable to general combining ability (gca) variance. The estimates of general combining ability effects in desirable direction for the grain mold resistance contributing traits along with grain yield per plant are presented in Table 2. 2, it was observed that five parents proved to be best general combining ability for the majority of the traits related to grain mold resistance. The parent AKGMR 118 has been found to possess significant desirable gca effects for all the grain mold resistance characters such as germination percentage, threshed grade mold rating (TGMR), grain density, grain hardness, electrical conductivity of grain leachates, glume coverage, fungal load of Fusarium spp., fungal load of Curvularia spp., fungal load of other mold spp. field grade mold rating (FGMR) and water absorption capacity along with grain yield per plant. The parent CSV 34 was found to be good combiner for most the grain mold resistance characters except for grain hardness, electrical conductivity of grain leachates, fungal load of other mold spp. and water absorption capacity. The parent CSV34 has been found to possess significant desirable gca effects for germination percentage, threshed grade mold rating (TGMR), grain density, fungal load of Fusarium spp., fungal load of Curvularia spp. and field grade mold rating (FGMR) along with grain yield per plant. The parent AKGMR 117 was found to be good combiner for almost all the grain mold resistance characters along with grain yield per plant. The parent AKGMR 117 has been found to possess significant desirable gca effects for germination percentage, threshed grade mold rating (TGMR), grain hardness, electrical conductivity of grain leachates, glume coverage, fungal load of Fusarium spp., fungal load of Curvularia spp., fungal load of other mold spp. field grade mold rating (FGMR) and water absorption capacity.

The parent PDKV Kalyani, transmitted favourable genes for the grain mold resistance characters along with grain yield per plant. It has recorded desirable significant gca effects for germination percentage, threshed grade mold rating (TGMR), grain density, glume coverage, fungal load of Curvularia spp. and field grade mold rating (FGMR).

Similarly, the parents viz., AKGMR 118, CVS 34, CSV 27, PDKV Kalyani and AKGMR 117 showed significant desirable gca effects for grain yield per plant. and found to be the best general combiner for grain yield per plant. (Table 2) . Thus, from summary performance of gca effects for grain mold resistance traits, from the above-mentioned parents four parents viz., AKGMR 118, CSV34, AKGMR 117 and PDKV Kalyani can be categorized as good general combiners for grain mold resistant traits along with grain yield per plant and may be utilize as a source of desirable gene in future breeding programme to exploit additive gene effects. Though the parent B58586 had negative gca effects for grain yield, but it had exhibited significant desirable gca effects for germination percentage, threshed grade mold rating along with most of the grain mold resistance contributing traits. Hence it may be included as a promising good general combiner parent in grain mold resistance breeding programme. Rao et al. (2016) [5] , Ingole et al.

(2018) [3] and Wawkar et al. (2023) [6] in their study also reported potential good combiners on the basis of GCA effects for grain mold resistance contributing traits. Since a high general combining effects correspond with additive and additive x additive interaction (Griffing 1956) [2] and represents the fixable genetic component of variation, hence these parents are considered valuable for use in recombination breeding programs.

Conclusion

The general combing ability effects for grain mold resistance traits, of the four parents viz., AKGMR 118, CSV34, AKGMR 117 and PDKV Kalyani can be categorized as good general combiners for grain mold resistant traits along with grain yield per plant and may be utilize as a source of desirable gene in future breeding programme to exploit additive gene effects. Additive and additive x additive interaction (Griffing 1956) [2] and represents the fixable genetic component of variation, hence these parents may be utilized in recombination breeding programme for development of grain mold resistance along with grain yield.

Acknowledgement

AcknowledgmentsI sincerely thank Dr. V. V. Kalpande, Senior Research Scientist (Sorghum), for his valuable guidance and support throughout the conduct of this research. I also extend my gratitude to the staff of Sorghum Research Unit, Dr. P D K V, Akola for providing the seed material and the necessary facilities required for the successful conduct of this research.

References

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4. Mofokeng MA, Shimelis H, Laing M, Shargie N. Sorghum (Sorghum bicolor (L.) Moench) breeding for resistance to leaf and stalk anthracnose, Colletotrichum sublineolum, and improved yield: progress and prospects. Australian Journal of Crop Science. 2017;11(9):1078-1085.
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