41 Indian Journal of Agricultural Sciences 93 (1): 41–45, January 2023/Article https://doi.org/10.56093/ijas.v93i1.105848 Relationship between heterosis, potence ratio and genetic distance for yield traits in maize (Zea mays) SUMALINI KATRAGADDA 1 *, PRADEEP TEKALE 1 and SRAVANI DINASARAPU 2 Agricultural Research Station, Professor Jayashankar Telangana State Agricultural University, Karimnagar, Telangana 505 001, India Received: 10 October 2020; Accepted: 6 December 2022 ABSTRACT An experiment was conducted during 2014–18 at Agricultural Research Station, Professor Jayashankar Telangana State Agricultural University, Karimnagar, Telangana to fnd out the relationship between heterosis, potence ratio and genetic distance for yield contributing characters in maize (Zea mays L.). Heterosis was trait dependent exhibiting high level for plant height, ear height, ear length, kernels/row, 100-kernel weight, grain yield and fodder yield. Two hybrids BML-51 × BML-14 (22.1%) and BML-51 × BML-6 (13.2%) recorded heterosis of greater than 10% over the check NK6240 and exhibited negative heterosis for fowering and maturity traits and positive heterosis for the remaining traits. Potence ratio indicated that majority of the traits in the hybrids had over dominance gene effect and expressed over dominance for ear length, ear diameter, kernels/row, fodder yield and grain yield suggesting heterosis breeding is an appropriate strategy for improvement of these traits. Standard heterosis of greater than 5% was observed in 7 crosses and out of these 6 belonged to mid parental divergence group. Five crosses, viz. BML-51 × BML-14, BML-51 × BML-7, BML-51 × BML-6, BML-32 × BML-13 and BML-32 × BML-6 with yield ranging from 7637 to 8733 kg/ha belonged to the medium parental divergence group comprising of high yielding inbreds, viz. BML-51 or BML-32 as parents. Grain yield heterosis was found signifcant and positively correlated with heterosis for ear length and 100-kernel weight. Therefore to maximize the full genetic potential of hybrids, inbreds with high per se performance and intermediate genetic divergence are to be involved in maize crop improvement programmes. Keywords: Heterosis, Maize, Potence ratio, Parental divergence, Single crosses 1 Professor Jayashankar Telangana State Agricultural University, Rajendranagar, Hyderabad, Telangana; 2 Agricultural Research Station, Professor Jayashankar Telangana State Agricultural University, Karimnagar, Telangana. *Correspondence author email: sumalinikatragadda@gmail.com Globally maize (Zea mays L.) is an important cereal crop because of its diverse uses mainly as food, feed and raw material for industrial products. In recent years the maize crop registered impressive production gains (both at global and national level) and this could be attributed largely to successful adoption of single cross hybrid technology. However, to match the growing requirement of the consumer across the globe there is an urgent need to further improve the productivity level especially in developing nations including India. Maize in Telangana state is an important crop occupying consistently an area of 6.5 lakh ha for the past 5–6 years but had shown a quantum jump of 3.0 t/ha in productivity (i.e. from 3.34 t/ha to 6.30 t/ha). This gain in productivity is attributed to post-rainy maize cultivation. Since the option for further increase in area is limited, a vibrant breeding programme needs to be adopted in hybrid development to enhance productivity across a range of production ecologies. Considering the above facts, the performance of single cross hybrids developed by involving newly developed potential inbreds was evaluated to estimate heterosis in comparison with mid and better parents along with popular hybrid check. Based on this data potence ratio was also determined during 2019 and an attempt has been made to fnd out the relationship between heterosis, potence ratio and genetic distance. MATERIALS AND METHODS Seven newly developed inbreds, viz. BML 51, BML 32, BML 14, BML 13, BML 10, BML 7 and BML 6 were crossed in diallel fashion (Griffng 1956 Method I Model II) to synthesize 21 single crosses in rainy (kharif) season, 2014 and the details of the inbreds used in this study have already been published in earlier paper (Sumalini et al. 2018). Using these 21 single crosses, 105 each of three-way and double cross hybrids were produced during post-rainy season, 2014–15. The performance of 21 single crosses and 105 each of three-way and double cross hybrids along with parents was tested during rainy season, 2015 against 18 hybrid checks at 3 locations, viz. Regional Agricultural