Agro-Morphological Evaluation of Converted Parental Lines and Reconstituted Hybrid Developed through Marker-Assisted Pyramiding of o2 and crtRB1 in Shalimar Maize Hybrid-7
Aman Tutlani
*
Division of Genetics and Plant Breeding, Faculty of Agriculture (FoA), Sher-e-Kashmir University of Agricultural Sciences and Technology of Kashmir (SKUAST–K), Wadura- 193 201, J & K, India.
Zahoor A. Dar
*
Dryland Agriculture Research Station (DARS), Rangreth, Srinagar- 190001, J & K, India.
Bhupender Kumar
ICAR-Indian Institute of Maize Research, New Delhi-110012, India.
M. Altaf Wani
Dryland Agriculture Research Station (DARS), Rangreth, Srinagar- 190001, J & K, India.
Parvaze A. Sofi
Division of Genetics and Plant Breeding, Faculty of Agriculture (FoA), Sher-e-Kashmir University of Agricultural Sciences and Technology of Kashmir (SKUAST–K), Wadura- 193 201, J & K, India.
N. S. Khuroo
Dryland Agriculture Research Station (DARS), Rangreth, Srinagar- 190001, J & K, India.
Asif B. Shikari
Division of Genetics and Plant Breeding, Faculty of Agriculture (FoA), Sher-e-Kashmir University of Agricultural Sciences and Technology of Kashmir (SKUAST–K), Wadura- 193 201, J & K, India.
Ajaz A. Lone
Dryland Agriculture Research Station (DARS), Rangreth, Srinagar- 190001, J & K, India.
Fehim Jeelani Wani
Division of Agricultural Economics & Statistics, Faculty of Agriculture (FoA), Sher-e-Kashmir University of Agricultural Sciences and Technology of Kashmir (SKUAST–K), Wadura- 193 201, J & K, India.
Sabina Nasseer
Dryland Agriculture Research Station (DARS), Rangreth, Srinagar- 190001, J & K, India.
Piyush Kumar
Division of Plant Pathology, Faculty of Agriculture (FoA), Sher-e-Kashmir University of Agricultural Sciences and Technology of Kashmir (SKUAST–K), Wadura- 193 201, J & K, India.
*Author to whom correspondence should be addressed.
Abstract
Marker-assisted gene pyramiding provides an efficient approach for incorporating multiple target genes into elite maize backgrounds while retaining desirable agronomic performance. The present study was undertaken to develop and agro-morphologically evaluate converted parental lines and reconstituted hybrids of Shalimar Maize Hybrid-7 (SMH-7) following marker-assisted pyramiding of the o2 (opaque-2) and crtRB1 genes. The breeding programme involved the conversion of the parental lines IML-187 and IML-418-1 through marker-assisted backcrossing, followed by foreground and background selection and phenotypic selection for desirable plant and grain characteristics. Selected BC₂F₂-derived lines were evaluated for phenological, plant, cob and grain-yield attributes and selected converted parents were subsequently used to reconstitute SMH-7. The IML-187-derived lines showed considerable similarity to the recurrent parent, with days to tasselling ranging from 73 to 77 days, days to silking from 77 to 80 days, plant height from 138.2 to 144.1 cm and grain yield from 59.9 to 66.8 g plant⁻¹. IML-187-SN-51-24-12 recorded the highest grain yield (66.8 g plant⁻¹) and favourable values for several yield-associated traits. The IML-418-1-derived lines exhibited days to tasselling of 76–78 days, days to silking of 80–82 days, plant height of 159.8–164.6 cm and grain yield of 51.0–57.1 g plant⁻¹. IML-418-1-SN-52-31-29 recorded the highest grain yield (57.1 g plant⁻¹) among the evaluated lines. Three reconstituted hybrids, Improved SMH-7-A, Improved SMH-7-B and Improved SMH-7-C, showed overall agro-morphological performance comparable to the original SMH-7. Improved SMH-7-C exhibited the highest grain yield among the improved hybrids (127.6 g plant⁻¹), along with superior performance for several cob and grain attributes, while the original SMH-7 recorded 129.5 g plant⁻¹. Thus, the study demonstrates that marker-assisted pyramiding combined with phenotypic selection can generate converted parental lines and reconstituted hybrids with substantial recovery of the elite agronomic background. Improved SMH-7-C and the identified converted parental lines represent promising breeding materials for further multilocation and multi-season evaluation.
Keywords: Marker-assisted selection, gene pyramiding, o2, crtRB1, converted parental lines, reconstituted hybrid, Shalimar Maize Hybrid-7