Combining ability studies in CGMS based hybrids of pearl millet [Pennisetum glaucum (L.) R. Br.]

Introduction

Pearl millet (Pennisetum glaucum (L.) R. Br.) is a key member of the Poaceae (Gramineae) family and the Pennisetum genus. Commonly known as bajra, bajri, cattail millet, spiked millet, and bulrush millet, this crop is highly cross-pollinated and features protogynous flowering with windborne pollination. These traits facilitate hybrid development and the commercial benefits of heterosis. In India, pearl millet is a major staple food, ranking fourth in acreage after rice, wheat, and sorghum, and it is the sixth most important cereal globally. Believed to have originated in tropical Western Africa around 4000 years ago, pearl millet is diploid, with a chromosome number of 2n=2x=14. The selection of appropriate parents for hybridization programme can be made on the basis of their ability to transmit desirable performance to their progenies (Yadav et al. 2005) [16] . The combining ability analysis helps in the evaluation of inbreds in terms of their genetic value, and in the selection of suitable parents for hybridization (Nambiar et al., 2011) [12] . It also helps in the identification of superior cross combinations which may be utilized for commercial exploitation of heterosis (Singh and Sharma 2014) [14] .

Materials and Methods

The experimental material comprised of nine CGMS (Female) lines viz., JMSA 1 20208, JMSA 5 20211, JMSA 4 20215, JMSA 4 20221, JMSA 4 20223, ICMA 1 17555, ICMA 4 18222, ICMA 1 93333, ICMA 1 97111; five restorer (male) lines of pearl millet viz., J-2296, J-2480, J-2571, J-2576, J-2604 and their 45 F 1 s hybrids developed by line × tester design and one standard check hybrid (GHB 1129). They were evaluated in randomized block design (RBD) with three replications at Main Pearl Millet Research Station, J.A.U., Jamnagar during kharif 2023. Row to row and plant to plant spacing was 60 cm × 15 cm. The observations were recorded on five randomly selected plants expect the plot basis from parents and crosses for 12 characters viz., days to 50% flowering, days to maturity, plant height, number of effective tillers per plant, earhead length, earhead diameter, dry earhead weight per plant, 1000-grain weight, dry fodder yield per plant, grain yield per plant, threshing index and harvest index. Mean data were used for statistical analysis. The total variation among F 1 hybrids was partitioned further into variance due to females, males and their interaction effects, which were used for combining ability analysis (Kempthorne, 1957) [7] .

Results and Discussion

The analysis of variance for combining ability revealed that mean squares due to lines, testers and lines × testers were tested against the error mean squares. If lines × testers interaction component was significant, the mean squares due to lines and testers were further tested against their respective interaction mean squares. The result revealed that the mean squares due to lines and testers were significant for all the characters under studied except earhead diameter due to lines. The result indicates that significant contribution of both line and tester toward total variation (Table 1). The mean squares due to lines × testers were found significant for all characters under study except days to maturity. The mean squares due to lines were also found significant for characters viz., days to 50 per cent flowering, plant height, earhead length, dry fodder yield per plant and grain yield per plant when tested against mean squares due to lines × testers interaction. Similarly, the mean squares due to testers were also found significant for days to 50 per cent flowering, earhead length, 1000-grain weight, threshing index and harvest index when tested against mean squares due to lines × testers interaction (Table 1). The estimated variance due to lines (σ 2 l) was higher than the corresponding variance due to testers (σ 2 t) for all the traits except days to 50 per cent flowering, days to maturity, earhead length, earhead diameter, 1000-grain weight, threshing index and harvest index. The estimated variance due to sca (σ 2 sca) was greater than the corresponding variance due to gca (σ 2 gca) for all characters under studied expect days to 50% flowering, days to maturity and earhead length Hence, variance ratio (σ 2 gca/ σ 2 sca) of all the characters except days to 50 per cent flowering and earhead length were resulted less than unity, suggesting the preponderance of non-additive gene action for all characters expect days to 50 per cent flowering and earhead length(Table 1). These results were in connection to the results obtained by Chaudhary et al. (2022) [3] , Keerthana et al. (2022) [6] , Choudhary et al. (2023) [5] , Maheswari et al. (2023) [10] , Solanki et al. (2023) [15] , Surendhar et al. (2023), Chinthakuntla et al. (2024) [4] , Moghariya et al. (2024) [11] and Pipariya et al. (2025) [13] . The parents were characterized for their ability to transmit desirable genes to their progenies. Among the parents, two females JMSA 4 20215 (5.62) and ICMA 1 17555 (1.06), and two male parents like J-2604 (1.57) and J-2296 (1.02) were found good general combiners for grain yield per plant (Table 2). The two female parent JMSA 4 20215 (5.62) and ICMA 1 17555 (1.06) displayed good general combiners for grain yield per plant JMSA 4 20215 also found good general combiners for plant height, number of effective tillers per plant, earhead length, dry earhead weight per plant, dry fodder yield per plant, threshing index and harvest index and the other female parent ICMA 1 17555 displayed good general combiners for grain yield per plant also found good general combiners for plant height, 1000-grain weight, and harvest index. Moreover, if we discuss about general combining of male parents, J-2296 found good combiner for grain yield was also recorded good gca effects in favorable direction for days to 50 per cent flowering, days to maturity, threshing index and harvest index. Likewise, parent J-2604 was noted to have greater potential to transmit useful genes for grain yield per plant, plant height, number of effective tillers per plant, dry fodder yield per plant and threshing index. Thus, the parents were good general combiners for grain yield per plant also showed good general combining ability for one or more component traits. These findings are in concurrence with results of Badurkar et al. (2018) [1] , Kumawat et al. (2019) [8] , Madane et al. (2023) [9] and Moghariya et al. (2024) [11] in pearl millet. Out of 45 crosses, 10 crosses manifested positive and significant sca effect for grain yield per plant (Table 3). The highest positive sca effect was observed in cross ICMA 4 18222 × J-2296 (6.16) followed by JMSA 4 20215 × J-2604 (4.84) and JMSA 5 20211 × J-2571 (4.09) for grain yield per plant. Hence, these crosses were identified as good specific combinations for grain yield per plant. The highest sca effect for grain yield per plant was manifested by ICMA 4 18222 × J-2296, which also exhibited significant sca effect in desired direction for earhead diameter, dry earhead weight per plant, threshing index and harvest index. This cross was involved poor × good general combining parents for grain yield per plant, fourth rank in per se performance and standard heterosis for grain yield per plant. The second highest sca effect in desired direction was recorded by cross, JMSA 4 20215 × J-2604 involved good × good general combiners parents for grain yield per plant, which also exhibited significant sca effect in desired direction for dry earhead weight per plant and dry fodder yield per plant. This cross was also manifested first rank in per se performance and in standard heterosis for grain yield per plant. Likewise, third highest significant sca effect in desired direction for grain yield per plant was recorded by cross JMSA 5 20211 × J-2571 had involved poor × average general combiners for grain yield per plant. The sca effect of grain yield per plant in this cross combination was also accompanied by sca effect for yield attributing traits viz., dry earhead weight per plant and dry fodder yield per plant. However, Chaudhary et al. (1974) [3] stated that high sca effect would not necessarily mean a high performance by the cross and the estimation of sca effect seemed to be superfluous, as no additional information was obtained by doing so. Therefore, it is suggested that the selection of parents for further breeding programme should be based on gca effect and due consideration should be given to mean value of the cross combination while selecting crosses for specific combining ability effect.

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