The utility of heterosis per se may not be of much use, but cross combinations showing excellent hybrid vigour can be used in developing high yielding forage hybrids in maize crop. The present investigation was conducted at B.A. College of Agriculture, Anand Agricultural University, Anand. The experimental material consisted of 50 F1 and their10 parents (5 females and 10 males). Material was sown in randomized complete block design with three replications. The hybrids were evaluated to know the extent of heterosis over better parent. The maximum heterobeltiosis for the most important character  green forage yield per plant observed in the hybrid IC 130882 × GDRFG 1644 (36.98). This hybrid can be identified as potential hybrid for wide spread cultivation and commercial exploitation after necessary testing. This cross can also be advanced for isolation of superior genotypes and selected genotypes may intermated to map up fixable genetic variance.

Forage Maize, Heterosis, Heterobeltiosis, Hybrid, Parents.

Maize (Zea mays L.) ranks second in position after sorghum among the cereal fodder crops. It is one of the most important dual purpose crops grown in kharif,  rabi and summer for grain and fodder purpose. Its quick growth and high palatability of fodder for cattle and wider adaptability over a wide range of environmental conditions and cropping seasons signifies as a good forage crop. It has no toxins and can be fed to the cattle at all growth stages in any quality. Indeed, maize green fodder has some lactogenic properties resulting in increased milk production. Hybrid vigor can be exploited in quantitative and quality traits in maize (Jogdande et al., 2024). Single cross hybrids also show good heterotic response (Sawan et al., 2022). Crosses made in Line × Tester fashion helps to predict heterotic response (Bichewar et al., 2023). It is also fact that very few hybrid varieties have been released in forage maize. Information available on heterosis breeding in forage maize is limited; hence, this attempt was made to investigate the extent of heterosis for forage yield and its attributing traits.

The field experiment was conducted at B. A. College of Agriculture Farm, Anand Agricultural University,    Anand during rabi-2023 season. The experiment was laid out in randomized block design (RBD) with three replications having a plot size of 4.5 m × 0.60 m. The present study consisted of a set of 5 lines (female parents) and10 testers (male parents). Parents were crossed in a line × tester mating design (5 × 10) in. Seeds of each entry were grown in two rows of 4.5 m length with 30 cm spacing between rows and 15 cm within rows. Recommended agronomic practices were followed for raising the crop. Observations were recorded on five randomly competitive plants for fodder yield and related traits. The data obtained for each character were analyzed  by  the statistical procedure given by Panse and Sukhatme (1989).

Heterobeltiosis (superiority over better parent) for all the characters were estimated while interpreting the results, positive heterobeltiosis effects were considered as favourable effect for the traits viz., plant height, number of leaves, leaf length, leaf width, leaf : stem ratio and green forage yield per plant. 

A. Plant height

Positive heterosis is desirable for plant height. Heterobeltiosis ranged from -11.93 to 26.31 (Table 1). Total five crosses were found significantly positive for heterobeltiosis in this character. The cross combination IC 130882 × IC 130987 (26.31) had significantly the highest estimate of heterobeltiosis. Similar results were also reported by Shete et al. (2011). 

Table 1: Heterosis in F1 hybrid over better parent (BPH) in forage maize.

Estimates of heterobeltiosis for number of leaves per plant varied from -12.20 to 31.14 (Table 1). Out of 50 crosses, 13 crosses had shown significant positive heterobeltiosis. The cross combination IC 7701 × OM 6357 (31.14) depicted the highest significant positive heterobeltiosis. These results were akin with reports of Patel et al. (2004).

C. Leaf length

Estimates of heterobeltiosis for leaf length varied from -8.56 to 12.21 (Table 1). Total 7  crosses were found significantly positive for heterobeltiosis in this character. The cross combination African Tall × IC 131016 (12.21) recorded significantly the  highest  heterobeltiosis  in desirable direction for  this trait. Similar results were also reported by Patel et al. (2004).

D.            Leaf width

For leaf width, the estimates of the range of heterobeltiosis was -14.85 to 18.10 (Table 1). Out of 50 crosses, 6 crosses had shown significantly positive heterobeltiosis. The cross combination IC 130882 × GDRFG 1644 (18.10) recorded significantly the highest heterobeltiosis effect among all crosses. Appreciable levels of heterobeltiosis for this character had been reported earlier by Choi et al. (1995); Patel et al. (2004).

E. Leaf : stem ratio

Positive heterosis is desirable for leaf : stem ratio. More leaves may increase the palatability of fodder. The estimates of heterobeltiosis ranged from -37.79 to 83.05 (Table 1). Total 5 crosses were found significantly positive for heterobeltiosis in this character. Among  the cross combinations, IC 7701 × IC 130976 (83.05) showed significantly the highest  heterobeltiosis  in desired direction. Similar results were also reported by Patel et al. (2004).

F. Green forage yield per plant

For most important character green forage yield per plant, the values of heterobeltiosis ranged from -20.43 to 36.98 (Table 1). Out of 50 crosses, 9 crosses exhibited significantly positive heterobeltiosis. Among the cross combinations, IC 130882 × GDRFG 1644 (36.98) depicted significantly the highest heterobeltiosis suggesting as good cross combination for this important character. Similar results were also reported by Mistry and Patil (1994); Santos et al. (1994); Patel et al. (2004).

The promising hybrids identified in this study can be exploited commercially to increase fodder yield in maize.

Nanavati J.I.  and Suvatar V.K.  (2024). Heterosis Studies for Yield and Yield Attributing Traits in Forage Maize (Zea mays L.). Biological Forum – An International Journal, 16(11): 119-121.