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The present research endeavour was executed with 59 rye introgressed wheat lines including 52 triticale × wheat stable lines and 7 wheat × rye (Lahaul Local) introgressed doubled haploids. The detection of new recombinants through molecular cytogenetic tools viz. genomic in situ hybridization and fluorescence in situ hybridization revealed 1BL.1RS translocation in 33 lines, 1BL.1RS translocation along with substitution in 5 lines, 1BL.1RS translocation along with addition in 8 lines, substitution of single pair of rye chromosomes in 5 lines and addition of rye chromatin in 1 line, while 7 lines were found with no rye chromatin. To validate the effect of rye introgression on drought tolerance and yellow rust resistance, all 59 recombinants were evaluated under well-watered and water stressed conditions at in vivo. Analysis of variance revealed sufficient genetic variability among genotypes for different traits at both in vivo level. Under field conditions, direct influence of rye introgression was observed on plant height, grain yield, biological yield and harvest index. Overall, 1BL.1RS translocations and substitutions were found to exhibit significant influence on most of the drought parameters. The screening for yellow rust resistance revealed differential disease reaction, where 52 recombinants were observed to be resistant. The lines exhibiting superiority for the traits can be used as a parental source in wheat improvement endeavours.

The ameliorative effect of seed priming with salicylic acid (SA) on Cr6+ and Zn2+ induced stress responses in wheat (Triticum aestivum L.) was evaluated using biochemical and computational approaches. The results suggested that Cr6+ and Zn2+ stress in wheat seedlings in absence of SA priming resulted in significant inhibition of growth, biomass loss with high accumulation of reactive oxygen species (ROS) leading to oxidative stress and inactivation of antioxidant metabolism. Wheat seeds primed with SA ameliorated the effects of Cr6+ and Zn2+ induced stress by maintaining appropriate growth and biomass of the seedlings. Moreover, when compared to the SA non-primed wheat seedlings, the levels of ROS and oxidative stress load were low in SA-primed seedlings subjected to Cr6+ and Zn2+ stress, which clearly indicated an ameliorative effect of seed priming with SA. Though, significant variation of antioxidant enzymes such as catalase (CAT) and superoxide dismutase (SOD) was not observed in wheat seedlings under stress conditions, and the non-enzymatic antioxidants such as ascorbic acid (AsA) and reduced glutathione (GSH) showed higher levels in SA-primed seedlings as compared to non-primed groups. The computational (molecular docking) analysis with Cu–Zn–SOD, Mn–SOD and CAT as target enzymes revealed that SA may potentially interfere with the binding and interaction of Cr6+ and Zn2+ ions with the active site of Cu–Zn–SOD effectively. Though, this computational analysis is based on structures of the targets derived through homology modeling, nevertheless it fundamentally substantiated our experimental findings on CAT and SOD activities.

To assess relative efficiency and identify efficient pollen source among maize and Imperata cylindrica for haploid induction, 21 maize and two Imperata cylindrica genotypes were hybridized as pollen parent with each of the four hexaploid, two tetraploid wheats and two genotypes of triticale following wheat × maize and wheat × Imperata cylindrica system of haploid induction. Observations for haploid induction parameters showed Imperata cylindrica as significantly superior pollen source than maize. Mean PFF, EFF, HRF and HFF obtained with Imperata were 55.05%, 24.07%, 18.58% and 4.96%, respectively, whereas the frequencies recorded with maize were 53.80%, 6.72%, 39.36% and 1.71%, respectively. Triticale remained nonresponsive to embryo formation with both the pollen species. The line × tester analysis showed significant effects of both male and female genotypes on all the haploid induction parameters. Analysis of GCA revealed differences among pollen sources in their potential to induce haploids. In maize, genotypes HPMC-57, HPMC-58, HPMC-25 for EFF and HPMC-58 for HFF emerged out to be best general combiners, while in the case of Imperata, GCA values were high for Ic-ye genotype. The present study put forth Imperata as an efficient pollen source over maize for haploid induction in hexaploid and tetraploid wheats.

Durum wheat × Imperata cylindrica hybridization was carried out utilizing two durum wheat genotypes as maternal parents (A-9-30-1 and PDW 314) and I. cylindrica as a pollen source followed by in vivo application of colchicine to establish a standard protocol for colchicine application aimed at enhancement of doubled haploid production in durum wheat. Various concentrations of colchicine ranging from 500 to 7000 ppm were injected to the pollinated spikes at different time interval viz., 24 h, 48 h and 72 h after pollination. Application of 5000–7000 ppm colchicine at 48 h after pollination was established as the optimum colchicine dose for chromosome doubling as confirmed through cytological studies in durum wheat using I. cylindrica-mediated chromosome elimination approach. PDW 314 was identified as a durum wheat genotype having more potential for doubled haploid induction via in vivo colchicine application than A-9-30-1. Identification of optimum dose of colchicine for application at in vivo level for induction of doubled haploids has opened new vistas in durum wheat improvement programme.

The investigation endeavored to study the distribution and allelic expressivity of hybrid necrosis genes (Ne1 and Ne2) in 332 maternal lines comprising 274 triticale × wheat derived homozygous recombinants, 41 winter × spring and spring × spring wheat derived doubled haploid lines, 12 reconstituted wheat lines and 5 released bread wheat cultivars of north-west Himalayan regions utilizing Himalayan genetic resources. Hybridization was executed at Palampur and Lahaul and Spiti, India by crossing maternal parents with two known tester parents C306 (NeNene2ne2) and HD2380 (ne1ne1NeNe) to generate F1 hybrids. The necrotic lines were categorized into Ne1 and Ne2-carriers based on the presence of necrosis genes in F1 hybrids. Subsequent screening revealed the presence of 83 Ne2-carriers (25%) and 249 non-carrier genotypes (75%) in the present study. Eighty-three Ne2-carriers comprised 51 triticale × wheat derived homozygous recombinants (11 Ne, 6 Ne, 26 Ne, 4 Ne and 4 Ne alleles), 22 winter × spring and spring × spring wheat derived doubled haploid lines (7 Ne, 12 Ne and 3 Ne alleles), 9 reconstituted wheat lines (5 Ne, 2 Ne and 2 Ne alleles) and 1 released variety (Ne allele) for necrosis and none of the lines possessed Ne1 gene. Analysis of Ne2 gene and their linkage properties with other paramount genes make Ne2-carriers superior source for emphasizing the genetic amelioration of wheat through selective hybridization.

Communicated by S.P. Baenziger) The present research endeavor was undertaken to depict the response of different generations viz., F1, F2, BC1F1, BC1F2, BC1F3, BC1F4 and BC1F5 of triticale × wheat and wheat × rye hybrids towards the different parameters of haploid induction. The experimental material included the different generations obtained utilizing five genotypes of triticale (DT-123, DT-126, TL-2900, TL-2908 and TL-9335), four genotypes of Himalayan rye (Karoki rye, shanoor rye, tino rye and triloki rye) with various elite bread wheat genotypes as parents in wide hybridization programme. The triticale × wheat and wheat × rye recombinants were further subjected to Imperata cylindrica-mediated chromosome elimination approach of doubled haploidy breeding. The variability in the haploid induction parameters was observed to be under genetic control for embryo formation and regeneration, while pseudoseed formation was only affected by auxin treatment. Among the different generations, the backcross generations viz., BC1F1 and BC1F2 were found to exhibit significant positive response towards haploid induction parameters in both triticale × wheat and wheat × rye hybridization. Knowledge of effective generation for haploid induction in triticale × wheat and wheat × rye hybridization not only saved the time and energy but also enhanced the efficiency of haploid induction.

An investigation to standardize the protocol for in vitro application of colchicine for enhancing the doubled haploid production in wheat was done. Two tetraploid (PDW-314 and A-9-30-1); and two hexaploid (DH-40 and C-306) wheat genotypes were used as maternal parents, whereas, the pollen sources involved Zea mays (cv. Bajaura Makka) and Imperata cylindrica. During the rabi seasons of years 2013–14 and 2014–15, wheat × maize and wheat × I. cylindrica hybridization was carried out followed by treatment of their haploids produced as a result of elimination of chromosomes of maize and I. cylindrica respectively, with varied doses of colchicine for different durations The various doses of colchicine were categorized into two groups: lower doses for longer durations (0.01, 0.025, 0.05% each for 5, 7, 9, 11 hrs) and higher doses for shorter durations (0.05, 0.075, 0.10, 0.15, 0.20, 0.25% each for 5, 4, 3, 2 hrs). The response of different concentrations of colchicine applied for varied durations revealed significant differences for various doubled haploidy parameters viz., per cent survived plants, per cent doubled haploid formation and per cent doubled haploid seed formation. In hexaploid and tetraploid wheats, colchicine doses of 0.075% for 4 hrs and 0.15% for 4 hrs, respectively were established as optimum for enhanced doubled haploid production.