Vol. 12, Issue 9 (2023)

Author(s):
Sivendra Joshi, Anil Kumar, JP Jaiswal, Usha Pant, Divya Chaudhary and Babita Bhatt

Abstract:
The frequency, duration, and severity of heat is aggravated by climate change. Under heat stress, the growth of the plant plays an important role in wheat. This study examines heterosis and combining ability under timely sown and heat stress of growth characters in wheat using line x tester mating design. Field experiments were conducted with eleven spring (8-line, 3-tester) wheat genotypes. The study unveiled diverse GCA effects for spike length, highlighting the positive impact of UP 262 in timely sown and UP 2572 in heat stress conditions. SCA effects varied across crosses, with VL 967 X QLD 91 showing strong positive SCA in timely sown environment and UP 2927 X QLD 91 in heat stress environment. For peduncle length, diverse GCA effects within parental lines were observed, including negative impacts of genotypes like PBW 725 in timely sown and VL 967 Under heat stress environment. Similarly, SCA effects across crosses varied, encompassing negative effects in cases like AGRA LOCAL X HS 490 Under timely sown and UP 3069 X HS 490 under heat stress. The study also unveiled significant positive relative heterosis and heterobeltiosis for cross UP 262 X QLD 91 under timely sown and heat stress, indicating potential for spike length improvement. Standard heterosis analyses highlighted the importance of AGRA LOCAL X DBW 222 in timely sown and UP 2572 X HS 490 in heat stress for enhancing spike length. Notably, significant negative relative heterosis, heterobeltiosis and standard heterosis was observed in in timely sown for cross PBW 725 X QLD 91 and for late sown highest relative heterosis and heterobeltiosis reported UP 2572 X QLD 91 and UP 2572 X DBW 222 for peduncle length. These findings contribute to our understanding of wheat enhancement and offer valuable guidance for future breeding endeavors.