Assessment of Molecular Genetic Diversity for Drought Tolerance in Sorghum [Sorghum bicolor (L.) Moench]
S. Isha Parveen *
Regional Agricultural Research Station, Acharya N.G Ranga Agricultural University, Nandyal - 518 502, India.
P. Shanthi
Regional Agricultural Research Station, Acharya N.G Ranga Agricultural University, Nandyal - 518 502, India.
C. V. Chandra Mohan Reddy
Regional Agricultural Research Station, Acharya N.G Ranga Agricultural University, Nandyal - 518 502, India.
R. Madhusudhana
Regional Agricultural Research Station, Acharya N.G Ranga Agricultural University, Nandyal - 518 502, India.
Shaik Nafeez Umar
Regional Agricultural Research Station, Acharya N.G Ranga Agricultural University, Nandyal - 518 502, India.
M. Redi Sekhar
Regional Agricultural Research Station, Acharya N.G Ranga Agricultural University, Nandyal - 518 502, India.
*Author to whom correspondence should be addressed.
Abstract
Stay-green is an important trait for improving drought tolerance and yield stability in sorghum under water-limited conditions. The present study aimed to assess the stay-green related molecular diversity and its association with grain yield in sorghum hybrids. Molecular analysis was conducted during rabi 2022–23 at RARS, Nandyal using sixteen F₁ hybrids along with two male sterile lines and eight restorers. Genomic DNA extracted through modified CTAB method was amplified using ten stay-green linked SSR markers associated with major loci Stg1, Stg2 and Stg3. Out of ten markers, seven were polymorphic and used for analysis. Molecular profiling revealed differential distribution of stay-green QTLs among parents and hybrids; AKMS66-2A possessed all three major QTLs (Stg1, Stg2 and Stg3), while 104A carried Stg1 and Stg2. Hybrids involving AKMS66-2A consistently exhibited favourable QTL combinations. Cluster analysis based on SSR data grouped the genotypes into four distinct clusters with a mean dissimilarity of 0.29, indicating moderate genetic diversity. Significant variation was observed for stay-green expression and grain yield among genotypes. The hybrid AKMS66-2A × R 3777 recorded the highest grain yield (4031.93 kg ha⁻¹) with a low stay-green score (1.28), followed by 104A × R 196 (3917.84 kg ha⁻¹; stay-green score 1.26). Superior hybrids with favourable stay-green QTL combinations demonstrated enhanced drought tolerance and can be effectively utilized in marker-assisted breeding programmes for developing climate-resilient sorghum hybrids.
Keywords: SSR markers, molecular diversity, sorghum, drought tolerance