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Open Access
Effect of farming practices on maize-wheat productivity, nitrogen dynamics, carbon sequestration and soil health in an acid Alfisol
(CSK HPKV, Palampur, 2023-07-13) Vishvamitera, Sakshi; Sharma, Sanjay K.
Imbalanced and sole application of chemical fertilizers has been found to adversely affect the crop productivity as well as the soil health. There is a ample scope to improve the production potential by manipulating nutrient management systems in such a way that these are more effective, environmental friendly, and largely acceptable. Therefore, the present study was undertaken to evaluate the effect of farming practices on productivity of maize and wheat, nitrogen dynamics, carbon sequestration and soil health. The experiment consisted of eleven treatments replicated thrice in a completely randomized block design, involving recommended NPK dose, 100% NPK+FYM@ 10 t ha-1 , 100% NPK+lime, organic farming practices, three natural farming systems involving formulations prepared using excreta of desi and crossbred cows, and buffalo, and their integration with 25% of recommended NPK dose. Application of 100%NPK + FYM@ 10 t ha-1 resulted in better crop growth and yield attributes, and registered the highest grain and stover/straw yield of maize and wheat, but these were statistically similar to 100% NPK + lime during both the years. For comparison of different treatments, maize grain equivalent yield and wheat grain equivalent yield were computed as NFS treatments included intercrops. Grain and stover/straw equivalent yield of maize and wheat were significantly higher under 100% NPK+ FYM@ 10 t ha-1 , which were however, statistically similar to 100% NPK+lime during both the years. Application of 100% NPK+ FYM@ 10 t ha-1 recorded 51.7% and 113.9% higher mean maize grain and stover equivalent yield, respectively, and 23.0% and 57.6% higher mean wheat grain and straw equivalent yield, respectively, than NFS-Desi cow. Integration of 25% NPK in these treatments significantly enhanced the yield over pure organic/natural farming treatments. The NPK and cationic micronutrient uptake by grain and stover/ straw of maize and wheat was highest in100%NPK + FYM@ 10 t ha-1 , and lowest in NFS-Buffalo treatment. Application of 100% NPK + lime increased the soil pH. Water holding capacity, mean weight diameter, organic carbon, available S, microbial count, microbial biomass carbon and nitrogen and enzyme activities were recorded highest in organic farming + 25% NPK treatment, however, available NPK were recorded highest under 100% NPK+FYM@ 10 t ha-1 , at both 0-0.15 m and 0.15-0.30 m soil depth. The highest content of inorganic N fractions were recorded under 100% NPK+FYM, while organic farming+ 25% NPK recorded the highest organic N fractions, and mean weight diameter at both the soil depths. Carbon sequestration was highest under 100% NPK+ FYM, while lowest was recorded under 100% NPK. Integration of 25% NPK with organic /natural farming systems significantly improved the soil physico-chemical properties at both soil depths over pure organic/natural farming systems. Among natural farming systems, NFS-Desi cow performed better in all the parameters as compared to NFS-Crossbred cow and NFS-Buffalo. Therefore, there was a notable effect of farming practices on maize-wheat productivity, nitrogen fractions, carbon sequestration and soil properties in an acid Alfisol, with conventional integrated nutrient management system giving the better results for most of the parameters under study.
Open Access
Molybdenum status and its critical limits for french bean and cauliflower in acid soils of Himachal Pradesh
(CSK HPKV, Palampur, 2023-07-11) Bijani, Hemali; Kumar, Pardeep
Molybdenum (Mo) an ultra-micronutrient plays key role in plants as an essential nutrient besides its significance in regulating nitrogen availability. It is emerging as a deficient nutrient especially in acid soils. As in Himachal Pradesh (HP), a significant area is under acid soils, likely to exhibit Mo deficiency. Since, no systematic study has been conducted on Mo status and its critical limits in soils and plants for french bean and cauliflower. Therefore, an investigation entitled "Molybdenum status and its critical limits for french bean and cauliflower in acid soils of Himachal Pradesh" was conducted from 2019 to 2022. The study involved the random collection of a total of 200 surface soil samples, analysed for soil pH, soil organic carbon (SOC) and available Mo through best extractant. The average soil pH was found to be 5.86, indicating slight acidity, while the mean SOC was determined to be 10.2 g kg-1 . Four extractants viz., Ammonium Oxalate (AO), EDTA, AB-DTPA, and Aqua Regia, were compared to assess their efficiency in extracting Mo on 40 segregated samples based on pH and SOC (20 each). Among these, Aqua Regia extracted pseudo-total Mo, exhibited the highest extraction rate with an average value of 0.41 mg kg-1 . Among rest of the three extractants, AO exhibited the highest extraction rate with an average value of 0.120 mg kg-1 followed by EDTA and AB-DTPA. The effectiveness coefficients of the extractants varied depending on the pH and SOC classes, with AO showing highest effectiveness at highest pH (>6) and SOC (>10.0 g kg-1 ) class. AO exhibited positive correlations with pH (0.334*), SOC (0.573**), N (0.526**), and P (0.461**), indicating a significant association between AO and soil properties. Spatial mapping of available Mo using the AO extraction method revealed a mean content of 0.122 mg kg-1 . The analysis indicated that majority of the samples exhibited latent deficiency of Mo (43%), followed by low (28.5%) and very low (6.5%). To establish critical limits of molybdenum (Mo) in soil and crops, a controlled pot experiment was conducted in a glasshouse. Ten different bulk soils (L1-L10) were selected, and six levels of Mo (0, 0.5, 1.0, 1.5, 2.0 and 2.5 mg kg-1 ) were applied to study their impact on the growth and yield of french bean (var. Falguni) and cauliflower (var. Pusa Snowball-K1). The experiment followed a completely randomized design with three replications. The results indicated that for cauliflower, increasing Mo levels up to 2.5 mg kg-1 was statistically at par with 2.0 mg kg-1 and resulted in improved growth parameters, yield attributes, yield, and nitrate reductase activity (NRA). Similarly, for french bean, Mo levels up to 2.0 mg kg-1 which was statistically at par with 1.5 mg kg 1 resulted in improved growth parameters, yield attributes, yield, and NRA. An increase in soil pH from 4.89 to 6.58 (L1-L5), and an increase in SOC from 2.90 to 15.1 g kg-1 (L6-L10), resulted in a significant and comparable improvement in crop yield in the Mandi (L4) and Hamirpur (L9) locations, whereas Sujanpur (L6) demonstrated the lowest performance with an SOC content of 2.90 g kg-1 . The post-harvest soil nutrient status showed that the effect of Mo levels were non-significant for available N, K, Mg and DTPA extractable micronutrients. Among locations, all the nutrients showed significant relationship. Critical limit for Mo in soil was worked out as 0.147 and 0.143 mg kg-1 for cauliflower and french bean, respectively. Critical limit of Mo for cauliflower and french bean in plant was figured out as 4.12 and 6.16 mg kg-1 , respectively. In conclusion, the study provided valuable insights into the distribution of available Mo in acid soils of Himachal Pradesh. The findings emphasized the importance of Mo for crop production and the established critical limits shall serve as a useful guideline for stakeholders.
Open Access
Effect of chemical fertilizers, organics and lime on fractions of micronutrient cations under continuous maize-wheat cropping in an acid Alfisol
(CSK HPKV, Palampur, 2023-02-10) Suri, Deepika; Sharma, R.P.
The present investigation was carried out in an on-going long-term fertilizer experiment, initiated during 1972 at experimental farm of Department of Soil Science, CSK HPKV Palampur, to study the effect of chemical fertilizers, organics and lime on fractions of micronutrient cations under continuous maize-wheat cropping in an acid Alfisol. The experiment was laid out in a randomized block design with twelve treatments. The soil of the experimental site was silty loam and classified taxonomically as “Typic Hapludalf”. Soil samples were collected after wheat (rabi, 2019-20 and 2020- 21) harvest from the surface (0-0.15 m) and sub-surface (0.15-0.30 m) layer. Soil samples were analyzed for various chemical, physical and microbiological properties using standard analytical procedures. Different fractions of Zn, Cu, Mn and Fe were determined in surface and sub-surface soil samples collected after wheat harvest (rabi, 2019-20) and soil samples drawn from adjacent buffer plots. The grain and stover/straw yield of maize and wheat was recorded. The nutrient concentration was determined in grain and stover/straw samples of maize & wheat and uptake was calculated. Continuous use of chemical fertilizers, organics and lime under maize-wheat system in an acid Alfisol brought out marked depletion in the pools of all the micronutrient cations as compared to buffer plots. The content of different fractions of Zn, Cu, Mn and Fe in sub-surface layer was less than that in surface layer. However, the treatment wise trend was almost similar to that under surface layer. Highest grain yield of maize (54.77 and 44.91 q ha-1 during 2019 and 2020, resectively) and wheat (28.11 and 24.67 q ha-1 during 2019-20 and 2020-21, respectively) was recorded under 100% NPK + FYM treatment which was at par with 100 % NPK + lime. FYM and lime treatments resulted in significantly higher uptake of all the nutrients by both the crops compared to other treatments. Most of the fractions of Zn, Cu, Mn and Fe correlated negatively and significantly with pH and positively and significantly with OC and CEC. Simple correlation and regression studies revealed that organically bound and exchangeable fractions were found to play major role in the nutrient supply, crop productivity and nutrients’ uptake.
Open Access
Effect of cropping systems on nutrient dynamics and soil health in an acid Alfisol
(CSK HPKV, Palampur, 2023-06-02) Choudhary, Deeksha; Datt, Naveen
The field experiment entitled “Effect of cropping systems on nutrient dynamics and soil health in an acid Alfisol” was undertaken at Bhadiarkhar experimental farm, Department of Agronomy, College of Agriculture, CSK HPKV, Palampur (H.P.) during 2019-2020 and 2020-21. The experiment consisted of ten cropping sequences viz., maize-wheat, maize-gobhi sarson + toria, dhaincha-early cabbage-french bean, sunhemp-vegetable pea-french bean, maize + soybean chickpea + linseed, rice-wheat + gram, hybrid sorghum + hybrid bajra-oats + sarson, hybrid sorghum + hybrid bajra-ryegrass + berseem, babycorn-broccoli-french bean and maize-turnip tomato in randomized block design which were replicated thrice. The soil of the site was acidic in nature (pH=5.5), silty clay loam in texture, medium in available nitrogen (350.6 kg ha-1 ) and potassium (147.3 kg ha-1 ) and high in available phosphorus (44.2 kg ha-1 ). Soil samples from 0- 0.15 m depth were collected before and after the harvest of each cropping cycle (2019-2020 and 2020-21) and analyzed for various physical, chemical and biological properties. In addition, different forms of nitrogen, phosphorus and potassium were also determined following standard analytical procedures. Maize-turnip-tomato recorded significantly higher maize grain equivalent yield, net returns and BC ratio. The total uptakes of N, P, and K in a cropping system were highest in sunhemp-vegetable pea-french bean while Fe, Mn, Zn and Cu uptake were maximum under maize-turnip-tomato. The cost of cultivation was highest for babycorn-broccoli-french bean cropping system due to labour intensive nature of vegetable crops in the sequence. The incorporation of green manures significantly improved the soil organic carbon content, cation exchange capacity, available N, P, K, S, exchangeable Ca and Mg, DTPA extractable Fe, Mn, Zn and Cu, microbial count of bacteria, fungi, actinomycetes, microbial biomass C, dehydrogenase acid phosphatase, urease and soil respiratory activity. Among N fractions, serine + threonine-N, total hydrolysable-N and Nitrate-N exhibited maximum correlation with total N uptake. Amongst P fractions, NaOH-Po, HCl-P and H2O-P for P uptake were found important. In case of K, water soluble-K and exchangeable-K were the dominant fractions. The N, P, K uptake and MGEY were found to be positively and significantly correlated with pH, SOC, CEC, MBC, dehydrogenase, acid phosphatase and SRA.
Open Access
Evaluation of crop sequences under natural farming, organic and integrated nutrient management production systems
(CSK HPKV, Palampur, 2023-07-06) Shalley; Pathania, Pawan
A field experiment entitled “Evaluation of crop sequences under natural farming, organic and integrated nutrient management production systems” was conducted during Kharif 2019-20 to Rabi 2020-21 at the Research Farm of Agronomy Department, College of Agriculture, CSK HPKV, Palampur to explore the production potential of identified cropping sequences and to monitor the change in soil fertility, quality and economic viability of the crop sequences. The soil at the experimental site was silty clay loam with an acidic reaction, medium organic carbon content, available phosphorus and potassium and low available nitrogen. The experiment consisted with sixteen treatments and three replications were laid out in split plot design. The treatments consisted of four production system viz. integrated nutrient management, organic farming, natural farming, conservation agriculture in main plots and in sub plots, maize - wheat, maize + cowpea - wheat + gram, maize + soybean-radish-onion and okra + pole bean - cabbage + garden pea were undertaken. In different cropping sequences, okra + pole bean – cabbage + pea sequence in combination with integrated nutrient management came out to be best in terms of maize grain equivalent yield (33009 kg ha-1 ) followed by organic farming system. However, integrated nutrient management in okra + pole bean – cabbage + pea sequence proved to be more economical and resulted in low cost of cultivation (₹146095 ha-1 ), high gross returns (₹523945 ha-1 ) and highest net returns per rupee invested (₹377850 ha-1 ). In terms of quality, integrated nutrient management production system with maize-wheat cropping sequence proved to be high in carbohydrate yield, fat yield and in energy equivalents. Integrated nutrient management with maize + soybean – radish – onion resulted in high protein yield. Application of conservation agriculture in combination with maize + cowpea- wheat + gram cropping sequence resulted significant increase in organic carbon, available nitrogen, phosphorus, potassium and also improve soil health of the system as microbial population in the soil i.e., bacteria and fungi were highest under conservation agriculture production system.
Open Access
Comparative performance of maize and wheat based intercropping systems under natural and organic farming practices
(CSK HPKV, Palampur, 2023-07-17) Raveena; Kumar, Rameshwar
A field experiment entitled “Comparative performance of maize and wheat based intercropping systems under natural and organic farming practices” was carried out at the Zero Budget Natural Farm (ZBNF), Department of Organic Agriculture & Natural Farming, CSK Himachal Pradesh Krishi Vishvavidyalaya, Palampur, from kharif 2020 to rabi 2021-22 to study the effect of natural and organic farming practices on the productivity, soil health and economics of maize and wheat based cropping systems. Soil of the experimental site was silty clay loam in texture, acidic in reaction, high in organic carbon and medium in available nitrogen, phosphorus and potassium. The experiment was laid out in randomized block design with three replications and thirteen treatments viz.,T1 - Maize + Lobia - Wheat + Gram and jeevamrit spray at 14 days interval, T2 - Maize + Lobia - Wheat + Gram and jeevamrit spray at 21 days interval, T3 - Maize + Lobia – Wheat + Gram and jeevamrit spray at 28 days interval, T4 - Maize + Soybean - Wheat + Lentil and jeevamrit spray at 14 days interval, T5 - Maize + Soybean - Wheat + Lentil and jeevamrit spray at 21 days interval, T6 - Maize + Soybean - Wheat + Lentil and jeevamrit spray at 28 days interval, T7 - Maize (sole) - Wheat (sole) and jeevamrit spray at 14 days interval, T8 - Maize (sole) - Wheat (sole) and jeevamrit spray at 21 days interval, T9 - Maize (sole) - Wheat (sole) and jeevamrit spray at 28 days interval, T10- Maize + Lobia – Wheat + Gram (Organic), T11- Maize + Soybean - Wheat + Lentil (Organic), T12- Maize sole - Wheat sole (Organic) and T13- Maize sole - Wheat sole (Absolute control). Significantly higher values of growth, yield attributes, grain and stover yield of maize were recorded under T1 during kharif 2020 and T4 during kharif 2021. Maize grain equivalent yield was significantly higher under T4 during both the seasons (2020 and 2021). In case of nutrient uptake, significantly higher nitrogen, phosphorus and potassium uptake by grain/seed, stover/straw as well as total uptake was recorded under T4 during kharif 2020 and T11 during 2021. In case of wheat, significantly higher growth and yield attributes were recorded under T1 during rabi 2020-21 and T11 during rabi 2021-22. Significantly higher grain and straw yield of wheat were obtained under T7 during 2020-21, while during 2021-22, it was higher under T12. However, there was an increment in the wheat grain equivalent yield of T10 and T11 by 26.89% and 45.58 % in rabi 2021-22 as compared to rabi 2020-21. Significantly higher nitrogen uptake by grain/seed, straw as well as total uptake was recorded under T10 during 2020-21 and T11 during 2021-22. However, highest phosphorus uptake by both grain/seed and straw as well as total uptake was recorded under T7 during first season and T11 during second season. In case of potassium, highest uptake by grain/seed was recorded under T11 during both the seasons, whereas straw as well as total uptake was highest under T7 during first season and T11 during second season. Amongst different intercropping systems, maize + soybean – wheat + lentil intercropping system along with application of jeevamrit at 14 days interval (T4 ) came out to be the best in terms of system equivalent yield (90.30 q/ha in 1st year and 82.53 q/ha in 2nd year) followed by organic farming practices, T11 (85.69 q/ha in 1st year and 81.83 q/ha in 2nd year). Use of natural farming practices in maize + soybean – wheat + lentil intercropping system (T4 ) also proved to be more economical and resulted in higher gross returns (249101 ₹/ha and 231759 ₹/ha), net returns (156061 ₹/ha and 132551 ₹/ha), B:C (1.68 and 1.34) and profitability (516.8 ₹/ha/day and 433.2 ₹/ha/day) of the system during both the years. Soil health was also significantly improved under organic farming treatment T11 in terms of organic carbon, available nitrogen, phosphorus, potassium and microbial count, microbial biomass carbon and dehydrogenase activity.
Open Access
Genetic analysis of seed yield and quality traits and molecular characterization for white rust resistance in Indian Mustard [Brassica juncea L. (Czern. & Coss.)]
(CSK HPKV, Palampur, 2023-08-03) Tiwari, Sunidhi; Kumari, Vedna
The p esent st entit e “Geneti ana sis o see ie an q a it t aits an mo e a ha a te ization for white rust resistance in Indian Mustard [Brassica juncea L. (Czern. & Coss.)]’’ was a ie o t to congregate information on genetic architecture, combining ability, heterosis and inheritance of white rust resistance. The materials for the investigation comprised of 12 lines, three testers (RCC-4, Donskaja-IV and their F1) and resulting 36 TTC hybrids. These progenies and their parents were grown in randomized complete block design with three replications during rabi 2021-22 at the Experimental Farm of the Department of Genetics and Plant Breeding, CSK HPKV, Palampur (H.P.). Analysis of variance indicated the significance of mean squares due to genotypes for all the traits which revealed the presence of sufficient genetic variability in the existing material. Modified triple test cross analysis exhibited the presence of epistasis for all the traits namely, days to flower initiation, days to 75 per cent maturity, plant height, reproductive phase, number of primary branches per plant, number of secondary branches per plant, siliquae per plant, length of main shoot, siliquae length, seeds per siliqua, 1000-seed weight, seed yield per plant, biological yield per plant and harvest index except for days to 50 per ent owe ing. F the , pa titioning o epistasis e ea e the impo tan e o ‘j ’ t pe o epistasis o a most all the t aits ex ept a s to 50 pe ent owe ing whe eas mean sq a es e to ‘i’ t pe inte a tion we e non significant for most of the traits except number of secondary branches per plant, siliquae per plant, siliqua length, seeds per siliqua, seed yield per plant and biological yield per plant which shows the importance of both ‘i’ t pe an ‘j ’ t pe o epistasis. Re ati e magnit e o a iti e omponent D) was p e ominant o e dominance component (H) for most of the traits except reproductive phase, number of secondary branches per plant, siliquae per plant and biological yield per plant indicating the relative importance of fixable type of gene action in their inheritance. Analysis of variance for line× tester revealed the presence of substantial genetic variability. Analysis of variance for combining ability indicated significant differences among hybrids for all the traits studied. The genotype DRMR 2017 was found to be good general combiner for nine traits followed by RSPR-03 for eight traits and Pusa Mehak for seven traits. Five crosses viz., Pusa Tarak × Donskaja-IV, Kranti × Donskaja-IV, RSPR-03 × Donskaja-IV, DRMR 2017 × RCC-4 and Urvashi × Donskaja-IV exhibited higher per se performance, significant SCA effects and heterobeltiosis for seed yield per plant. Two crosses namely, Urvashi × Donskaja-IV and Pusa Tarak × F1 showe ow g osino ate ontent ˂30 µmole per gram of defatted seed meal) and only one genotype viz., Pusa Karishma showed low erucic acid ˂ 2 pe ent). To study the inheritance of white rust resistance, two crosses (RCC-4 × Donskaja-IV and RCC-4 × Heera) were evaluated. In cross RCC-4 × Donskaja-IV, dominant epistasis (12:3:1) was observed while in cross RCC-4 × Heera, complementary epistasis (9:7) was observed. Molecular characterization revealed that intron polymorphic (IP) markers viz., At5g41560 and At2g36360 were highly linked to white rust resistance loci AcB1-A4.1 and AcB1- A5.1 and could be helpful in marker assisted selection for white rust resistance in Indian mustard.
Open Access
Induced mutagenesis and molecular characterization of elite mutants for grain quality in bread wheat (Triticum aestivum L.)
(CSK HPKV, Palampur, 2023-06-23) Rana, Amit; Rana, Vijay
Present studies were conducted with four wheat varieties viz., HS 490, HPW 89, HPW 360 and HPW 251, mutagenized using 175 Gy, 200 Gy, 225 Gy, 250 Gy, 275 Gy & 300 Gy of gamma rays (γ) and 0.3%, 0.5%, 0.7%, 0.9%, 1.1% & 1.3% of EMS to assess their mutation effectiveness and efficiency, spectrum of induced macro mutations in M1 and M2 generation at the Experimental Farm, Rice and Wheat Research Centre, Malan during Rabi 2020-21 and 2021-22. Results showed similar trend of reduction in different parameters with increase in dose/concentrations of both mutagens under lab and field conditions in M1 generation. The LD50/LC50 values of four wheat varieties varied between 290-315 Gy and 0.90-1.35% in case of γ-rays and EMS under lab conditions whereas 240-290 Gy and 0.50-1.10% in case of γ-rays and EMS under field conditions. HPW 251 was found to be more sensitive to both mutagens whereas, HPW 89 emerged as relatively less sensitive to γ-rays and HS 490 to EMS. These results indicated higher sensitivity of semi-hard varieties to mutagens as compared to soft-textured varieties. In M2 population of 18,862 plants, a broad spectrum of chlorophyll mutants (0.949%) and morphological mutants (4.135%) were observed. Mutagenic effectiveness and efficiency showed that highest estimates were found at higher concentrations, but the estimates changed non-linearly with increase in concentrations over all four varieties for both the mutagens. Overall, HPW 251 was found to be most sensitive for mutagenic treatments as compared to HPW 360, HPW 89 and HS 490. EMS caused higher shift in magnitude of all the parameters studied as compared to γ-rays. Based on LD50, three doses (250 Gy, 300 Gy & 350 Gy) of γ-rays were used for inducing mutations in wheat variety HPW 89. Five mutagenic generations viz., M1, M2, M3, M4 and M5 of HPW 89 were raised and studied using Rabi seasons and off-seasons through 2019-2022 at the Experimental farm, RWRC, Malan; HAREC, Kukumseri and IIWBR Regional Station, Dalang maidan, L&S to select agro-morphologically superior, disease resistant and better-quality mutants. Presence of significant variation among 293 M4 mutant lines indicated the scope of selecting desirable mutants for various agro-morphological and quality traits. High phenotypic coefficient of variation and genotypic coefficient of variation as well as high estimates of broad sense heritability coupled with high genetic advance for flag leaf length, flag leaf area, peduncle length, biological yield/plant and grain hardness that selection based on these traits would be effective and rewarding. Days to 50% flowering, days to 75% maturity, biological yield/plant, harvest index and grain hardness emerged to be suitable selection criteria for grain yield improvement on the basis of correlation and path analysis. Out of 108 semi-hard elite mutants, 8 mutants viz., Mut9, Mut17, Mut58, Mut104, Mut109, Mut126, Mut179 & Mut195 were found superior with higher grain hardness, better grain appearance score, sedimentation value and protein content as compared to parent variety HPW 89. These mutants can be further subjected to multi-location testing before channelizing them into the breeding programmes. Overall, two mutants viz., Mut9 and Mut17 were found promising for grain yield, resistance to yellow rust and powdery mildew and desirable quality parameters. Molecular characterization of 108 semi-hard mutants showed presence of both pina and pinb genes. However, mutants having higher grain hardness as compared to parent variety HPW 89 suggested mutations in one or both genes and ma
Open Access
Molecular diversity analysis and genetics of some morpho physiological and biochemical traits associated with moisture-stress tolerance in bread wheat (Triticum aestivum L.)
(CSK HPKV, Palampur, 2023-03-25) Anubhav, Shubhanshu; Rana, Vijay
The present investigation entitled ‘Molecular diversity analysis and genetics of some morpho-physiological and biochemical traits associated with moisture-stress-tolerance in bread wheat (Triticum aestivum L.)’ was conducted to identify morpho-physiological and biochemical traits associated with moisture-stress tolerance and analyze genetic diversity at morphological and molecular level. Experimental material for diversity studies comprised of 56 genetically diverse wheat genotypes; including some high yielding, drought tolerant lines, synthetics, local collections, recombinant inbred lines of a drought tolerant cultivar C 306. Experimental lines were evaluated for different traits in alpha-RBD design with three replications under irrigated (E1) and moisture-stress (E2) field conditions during Rabi 2017-18. A modified TTC analysis comprising 48 progenies; 16 lines and 3 testers was conducted under controlled irrigated (E1) and moisture-stress (E2) conditions during Rabi 2018-19. Significant genetic variability was observed for days to 50% flowering, flag leaf area (FLA), specific leaf area (SLA), specific leaf weight (SLW), relative water content (RWC), grain growth rate I (GGR-I), grain growth rate II (GGR-II), stem reserve mobilisation (SRM), tillers/ plant, grains/ spike, 1000-grain weight, biological yield/ plant, dry matter accumulation (DMA), grain yield/ plant, harvest index and proline content. High phenotypic coefficient of variation (PCV) and genotypic coefficient of variation (GCV) along with high heritability and moderate genetic advance were recorded for proline content under E1 and E2. Grain yield/plant showed significant positive correlation with tillers/plant, 1000-grain weight, biological yield/plant, DMA and harvest index. Biological yield/ plant and harvest index appeared to be the best selection indices for increasing grain yield owing to high direct and indirect effects of these traits in path analysis. Under E1 first six principal components revealed 72.40 % and under E2 first five components explained 71.6 % of total variability. Variation for proline content contributed the maximum to the observed genetic divergence under both conditions. Congruence between morpho-phyiological and SSR data was observed under both the environments. Forty-six out of 56 test genotypes were common among molecular and morphological clusters under moisture-stress, whereas 39 genotypes were common under irrigated conditions. Genotypes SYN 105, IC 36737, HS 562, IC 594376 and VL 907 under irrigated conditions and genotypes viz. IC 322025, HS 490, VHC 6081, VHC 6127, SYN 103, VL 892, VHC 6413, C 306, VL 907, HPW 236 and SYN 117 under moisture-stress conditions were most diverse. STRUCTURE divided the experimental lines into two major populations. Modified TTC analysis was used to detect epistasis and estimates of additive and dominance components of variance for observed phenotypes, which indicated that mean squares due to epistasis were significant for all the traits except SLW and relative water content under irrigated conditions (E1) and FLA under (E2). Additive × Additive (i) type interactions were significant for GGR-I and tillers/ plant under E1 and E2 conditions while j+l type interactions were significant for all the traits except SLW and RWC under irrigated conditions (E1) and RWC under E2. The average degree of dominance (H/D)1/2 revealed similar gene action for 1000-grain weight and GGR-II under both E1 and E2. The comparison of estimates of genetic parameters using Line × Tester and Triple test cross indicated the role of overdominance in genetic control of traits namely, grains/spike, grain growth rate I and proline content under both the environments E1 and E2. Combining ability analysis revealed VHC 6413, HS 562, NIAW 1415, WH 1105 as good general combiners for FLA, GGR- II, grains/ spike, 1000-grain weight; Syntehtic 107 and NIAW 1415 for SRM; VHC 6081 and VHC 6127 for tillers/plant; HS 490,VHC 6127 and HS 507 for DMA; VHC 6127, HS 490, NIAW 1415 and NI 5439 for grain yield/plant; HS 562 and Synthetic 107 for harvest index; HS 507, Synthetic 107, Synthetic 112 and NIAW 1415 for proline content under both E1 and E2. HPW 89 x VL 907 recorded positive significant SCA effects for GGR- II; HPW 349 × VL 907 and HS 562 × HPW 368 for stem reserve mobilisation and VHC 6127 × HPW 368 for grains/spike and dry matter accumulation. These crosses were found promising and could be utilized for developing high yielding drought tolerant lines.

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