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Open Access
Morpho-physiological and biochemical characterization of a recombinant inbred line population of rice (Oryza sativa L.) under direct-seeded aerobic conditions
(Punjab Agricultural University, Ludhiana, 2014) Cheema, Amandeep Kaur; Bedi, Seema
Direct seeding of rice (Oryza sativa L.) is a resource conservation technology but at the cost of reduction in yield. In the present study, recombinant inbred lines (RILs) obtained from a cross between PR 120 x UPLRi 7 were sown as direct-seeded aerobic and conventional transplanted crops respectively for two seasons. Various morpho-physiological, biochemical and yield related traits were studied under the two conditions. In general, plant height, dry matter, crop growth rate, relative growth rate, leaf area and chlorophyll content were lower under direct-seeded aerobic conditions than under conventional transplanted conditions. Plant height and crop growth rate showed a positive correlation with grain yield and had a direct effect on grain yield. Dry matter accumulation did not show any significant correlation but had an indirect effect on grain yield. Relative growth rate, leaf area and chlorophyll content did not show any correlation or effect on grain yield. All the yield contributing traits viz., above ground biomass, total number of tillers per 0.5m row, number of fertile tillers per panicle per 0.5m row, spikelets per panicle, grain filling percentage, grain yield per 0.5m row, harvest index, 1000 grain weight were lower and sterile grain per panicle were higher in direct-seeded aerobic condition. Above ground biomass and harvest index showed correlation with yield and had a direct effect on grain yield under both direct-seeded aerobic and conventional transplanted conditions. In general, higher sugar, starch and proline content were detected in leaves of direct-seeded aerobic crop. Out of twenty RILs under study, Ae-RIL-B-158, showed highest proline and sugar contents. Interestingly, this RIL showed least reduction in yield when sown under direct seeded-aerobic condition as against conventional transplanted condition suggesting this RIL may be more tolerant to drought stress as it accumulated highest proline and sugars under direct-seeded aerobic condition. The development of aerenchyma was comparatively more in crop raised under conventional transplanted conditions than under direct-seeded aerobic conditions. UPLRi7 (parent) showed maximum aerenchyma under direct-seeded aerobic conditions while PR120 (parent) showed maximum aerenchyma formation under conventional transplanted conditions. Under both the sowing conditions, two high-yielding RILs (Ae-RIL-B-42 and Ae-RIL-B-44) had higher aerenchyma than the two low-yielding RILs (Ae-RIL-B-7 and Ae-RIL-B-117). These characters could be used as criteria for selecting RILs for incorporating into breeding programmes for yield enhancement.
Open Access
Morpho-physiological characterization of Mexican wheat landraces for traits of Economic importance
(Punjab Agricultural University, Ludhiana, 2018) Ankita; Sarlach, R.S.
The present research work on “Morpho-physiological characterization of Mexican wheat landraces for traits of Economic importance” was carried out to explore the genetic diversity of landraces for drought and salinity stress tolerance. The study was carried out at wheat laboratory and experimental area of Department of Plant Breeding & Genetics, Punjab Agricultural University, Ludhiana during 2015-16 and 2016-17. A set of 1161 Mexican wheat landraces was procured from CIMMYT, Mexico and was sown in field in augmented block design. The landraces set was narrowed down to a smaller set on the basis of their yield potential and seed availability. Selected 177 Mexican wheat landraces were subjected to salinity and drought stress conditions. To find the salinity stress tolerance among Mexican wheat landraces, they were subjected to different concentration of sodium chloride (0, 25mM, 50mM, 75mM, 100mM, 125mM and 150mM) in laboratory. Among different concentration of NaCl, 125mM was found to be the optimum dose for screening. Similarly, to find the drought stress tolerance among Mexican wheat landraces, these were subjected to different concentration of PEG (6000) 0 (control), 2%, 4% 6% 8%,10%,12%,14%,16% and 18%.Dose of 14% was found to be the optimum dose for further screening. The landraces selected from the laboratory screening at seedling level were further evaluated for drought stress (irrigated, restricted irrigated and rainfed conditions) and salinity stress tolerance (Rajpura and Rattakhera, Sri Muktsar Sahib) under actual field conditions and in pots with simulated salinity stress conditions (control, 120mM and 240mM NaCl).The soil of Sri Muktsar Sahib was slightly alkaline having pH 8.1 and high EC (0.948 dS/m). The district contains high salinity and water logged area. And the soil of Rajpura was alkaline having pH 8.5 and high EC (1.97 dS/m). The landraces MICH89.4.28, MICH89.5.5, VERY LATE, HGO94.10.7, MEX94.19.52 performed well under actual field and simulated salinity stress conditions. The drought stress was created by withholding of irrigations (rainfed conditions) pre-irrigation before sowing and subjected to rainfall for water requirements, irrigated conditions (regular recommended irrigation) and restricted (1-2 irrigation after sowing). The morpho-physiological data was recorded. The landraces TXL92.1.1.58, PBL94.14.17, HGO94.5.124, HGO94.5.130, HGO94.9.2.29 and HGO94.8.113 performed well under drought stress conditions. These landraces can be used for introgressing the salt and drought tolerance traits into commercial wheat cultivars for development of tolerant wheat varieties.
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Partitioning of zinc and its associated metabolites in diverse rice (Oryza sativa L.) genotypes
(Punjab Agricultural University, Ludhiana, 2018) Avneet Kaur; Nirmaljit Kaur
The present investigation entitled “Partitioning of zinc and its associated metabolites in diverse rice (Oryza sativa L.) genotypes” was undertaken in the Department of Botany, Punjab Agricultural University, Ludhiana during 2016-17. Seeds of sixteen genotypes with diverse zinc content were procured from the Department of Plant Breeding and Genetics, Punjab Agricultural University, Ludhiana. The studies were conducted in two experiments, in the first experiment sixteen rice genotypes were raised in the nursery and; physiological and biochemical parameters of rice genotypes were quantified from 35-days old seedlings. The chlorophyll pigments, hill activity, total soluble sugars, total soluble proteins, free amino acids, starch and superoxide dismutase (SOD) activity were recorded higher in PR113 and PR121, whereas these were lower in RYT Biofort1 and RYT 3403 as compared to the rest of the genotypes. Grain weight, grain yield and grain zinc uptake also followed similar trend. Hence, PR113 and PR121 were characterized as zinc efficient, whereas, RYT Biofort1 and RYT 3403 as zinc inefficient. These zinc efficient and zinc inefficient genotypes were put to further experimentation. The zinc content and zinc associated traits were quantified during three stages of development: maximum tillering, anthesis (50% flowering) and maturity. The chlorophyll content, hill activity and SOD activity increased significantly from maximum tillering to anthesis stage and these parameters were also higher in zinc efficient genotypes as compared to zinc inefficient genotypes. The total soluble sugars, total soluble proteins, free amino acids and starch increased significantly from maximum tillering to anthesis stage, whereas decreased from anthesis to maturity. These metabolic reserves were higher in zinc efficient genotypes as compared to the zinc inefficient genotypes. The plant height, leaf area, flag leaf area, leaf weight, number of tillers and internodal length was also higher in zinc efficient genotypes as compared to the zinc inefficient genotypes. The leaf, tiller, spike and grain were separated at each representative stage of growth for quantifying weight, zinc content and zinc uptake. A higher dry matter accumulation as well as zinc remobilization from the vegetative to reproductive parts of the plant was observed in the zinc efficient genotypes as compared to the inefficient ones.Panicle characteristics, viz., panicle length, panicle number per m2, filled spikelet percentage and percent grain filling were high in zinc efficient genotypes, whereas low in zinc inefficient genotypes. On the contrary, panicle sterility was high in the zinc inefficient genotypes. Yield and yield contributing traits, viz., test weight, grain weight per plant, grain yield and harvest index were high in the zinc efficient genotypes as compared to the zinc inefficient genotypes. Based on the present investigation, PR113 and PR121 have been characterized as zinc efficient and RYT Biofort1 and RYT 3403 as zinc inefficient genotypes.
Open Access
Morphophysiological basis of manganese deficiency tolerance in progenies derived from wheat  triticale crosses
(Punjab Agricultural University, Ludhiana, 2018) Ramanjit Kaur; Sarlach, R.S.
Manganese (Mn) is one of the leading micronutrient deficiency disorders in alkaline and calcareous soil of Punjab due to wheat-rice crop rotation system. Mn efficiency is an ability of a plant to have greater Mn uptake in the Mn deficient soil too. This study was designed to refine the half seed technique for screening of efficient progenies derived from wheat x triticale crosses at seedling stage on the basis of specific visual symptoms of Mn deficiency in the pot experiment and then validated in the Mn deficient field. Taking in account its traits to be introgressed from rye and the preliminary indications of micronutrient deficiency tolerance, the proposed study has been devised to explore the potential of Mn deficiency tolerance in the germplasm. In the first pot experiment, nine wheat genotypes were sown using half and full seed under Mn deficient conditions. Being most sensitive to Mn deficiency durum wheat cultivar PDW 233 showed earliest symptoms in half seed rather than full seed. It helped to validate the method of screening. This novel method of screening was used to evaluate lines derived wheat x triticale crosses. Durum wheat, bread wheat and triticale were used as standard sensitive, moderate and tolerant control respectively. Out of seventy two lines, only forty two were selected on the basis morpho-physiological traits like root-shoot length (cm), dry matter accumulation (g), days to germination (DTG), vigour index, relative growth rate, days to deficiency symptom appearance, yield contributing traits, Mn indices and stress tolerance index. Biochemical analysis of selected lines was carried out later in laboratory. Lines derived from first cross TL2908/2*CS(S)//PBW343 were 3-TL to 5-TL, 8-YRR-TL, 12-TL, 14-TL, 15-YRR-TL, 21-TL to 26-TL, second cross T3048/2*CS(S)//PBW343 were 28-T3048 to 38-T3048, 43-T3048, 46-T3048 to 48-T3048, 51-T3048, third cross 54-T3065/2*CS(S)//PBW343, forth cross 56-T3048/2*CS(S)//DBW17 to 59- T3048/2*CS(S)// DBW17, 61-T3048 to 63-YRR-T3048 and fifth cross 65-T3021/2*CS(S)//PBW550 to 66-T3021/2*CS(S)//PBW550, 68-T3021, 71-T3021 to 72-YRR-T3021 were evaluated as Mn efficient lines. These lines can be used for further processing to introgress Mn efficiency and released at commercial level as Mn deficiency tolerant varieties.
Open Access
Growth and development of wheat (Triticum aestivum L.) genotypes as affected by drought stress and PGRs
(Punjab Agricultural University, Ludhiana, 2017) Aparjot Kaur; Thind, S.K.
The most important challenge in production of most of the crops including wheat (Triticum aestivum L.) is drought stress. Presently, growth and development of wheat genotypes (HD2967, PBW660, WH1105 and PBW658) as effected by drought stress and plant growth regulators like cytokinins [Kinetin (Kn) and Benzyl adenine (BA)] on various morpho-physiological and biochemical parameters under the lab conditions were studied to select the best concentration of Kn (@ 10, 20 and 40mg/L) and BA (@ 25 and 50mg/L). Drought stress in laboratory was induced by PEG-6000 creating -0.4MPa of stress. Under laboratory conditions, Kn@40mg/L and BA@50mg/L was performed better as compared to lower concentrations of Kn and BA tested and these were studied in combination with osmoprotectants like [Trehalose (Tre) and Glycine Betaine (GB)] in different combinations like Kn@40mg/L along with Tre@1mM, Kn@40mg/L along with Tre@ 1.5mM, BA @50mg/L along with Tre@1mM, BA @50mg/L along with Tre @ 1.5mM, Kn@40mg/L along with GB 50mM, Kn@40mg/L along with GB100mM, BA @50mg/L along with GB 50mM, BA @50mg/L along with GB 100mM in the field experiments on three wheat genotypes (HD2967, PBW660 and WH1105. Drought stress significantly reduced various morpho-physiological parameters like Relative Growth rate (RGR), Specific leaf area (SLA), Relative leaf water content (RLWC) and photosynthetic gas exchange parameters like net photosynthetic rate (NPR), transpiration rate (TR), stomatal conductance (SC) and intercellular CO2 concentration (ICC) at vegetative as well as flag leaf stage. Cytokinins along with different concentrations of osmoprotectants significantly decreased the negative effect of drought stress on various morpho-physiological parameters. Significant negative effect of drought stress was studied on biochemical parameters like Hill reaction activity, MDA content, membrane stability and cell viability. Drought stress significantly increased the photosynthetic pigments like chlorophyll and carotenoid content. Drought stress significantly increased the total soluble sugars, reducing sugars and decreased the non-reducing sugars. Enzymatic activities of various antioxidants like SOD, catalase, APx, DHAR and MDHAR were increased significantly under drought stress. Nonenzymatic ROS were alleviated significantly under drought stress and by application of cytokinins in combination with osmoprotectants. Under drought stress a significant reduction in yield contributing parameters like number of kernels per spike, number of productive tillers/m2, peduncle extrusion, thousand grain weight, grain yield/m2, biological yield/m2 and harvest index was recorded. Cytokinins in combination with different concentrations of osmoprotectants significantly ameliorated the negative effect of drought stress. From among the tested combinations, Kn@40mg/L in combination with Tre@ 1.5mM had more pronounced effect in ameliorating the adverse effect of drought stress on yield contributing parameters of selected wheat genotypes.
Open Access
Effect of plant growth regulators on manipulation of source-sink relationships in pigeonpea (cajanus cajan l.)
(PAU, 2013) Pahwa, Kanchan; Ghai, Navita
Field experiments were conducted at Punjab Agricultural University, Ludhiana during kharif season in the years 2010-11 and 2011-12 respectively with an objective to evaluate various groups of genotypes (early, mid, late and check) on the basis of pattern of growth, partitioning of dry matter, flower retention, growth efficiency and yield and to study the effect of foliar application of ethrel (100 and 200 μg ml -1 ) and cobalt chloride (10 and 15 μg ml -1 ) applied at vegetative and flowering stages on seed yield. Various morpho-physiological, biochemical and yield characteristics were analyzed at different developmental stages. Study conducted with early, mid, late and check genotypes of pigeonpea revealed marked differences in partitioning of assimilates to vegetative and reproductive parts at different stages of growth cycle. The higher CGR, RGR, leaf area, LAI, photosynthesis, stomatal onductance, pod set percentage in mid-duration group resulted in high yield. Further, reproductive efficiency of four mid-duration genotypes (AL 1578, AL 1593, AL 1702 and AL 201) was chemically manipulated by foliar application of ethrel and cobalt chloride. The parameters determining reproductive efficiency and yield were significantly improved due to reduction in flower abscission. Ethrel (100 and 200 μg ml -1) sprayed at vegetative stage and CoCl2(10 μg ml-1) sprayed at flowering stage efficiently improved seed yield and other biochemical traits through improved flower retention, pod formation , seed setting percentage and seed weight. Genotype AL 1578 exhibited high yield in all treatments including control as compared to all the genotypes. The leaves of treated plants exhibited higher level of chlorophyll, which provided better conditions for higher production of photosynthates to be utilized for grain yield due to larger sink resulting from increased branching and number of pods. The treatments also affected the content of various biochemical constituents (total soluble sugars, total soluble proteins, total starch content, total free amino acids, chlorophyll content as well as the activity of various enzymes viz., nitrate reductase (NR), invertase and PEP carboxylase). Correlation analysis showed significant positive relationships between plant height, crop growth rate, leaf area, number of pods/plant, pod set percentage, seed eight/plant, 100-seed weight and harvest index. Further, path analysis revealed leaf area, specific leaf weight and number of pods/plant had significant positive direct influence on yield. Path analysis of various biochemical traits with seed yield revealed that activities of nitrate reductase, total soluble proteins and total starch content in leaves and invertase activity, total starch in seeds showed positive direct effect on seed yield. These traits should be used as target traits to improve seed yield. Protein profiling in mature seeds revealed much denser bands in treated plants as compare to control and also number of bands were higher in treated plants. A study of pedicel anatomy revealed an increase in area of conducting tissues through PGRs application. This increase could be responsible for enhanced translocation of assimilates to flowers, thereby helping in their retention.
Open Access
Physiological evaluation of source-sink relationships in soybean (Glycine max L. Merrill) genotypes under variable photoperiods
(PAU, 2014) Dogra, Anil kumar; Kaur, Jagmeet
Soybean is a short day plant. Both photoperiod and temperature control the duration of pre and post flowering phase and are expected to affect source-sink relationships. The present investigations were aimed at evaluating the relative performance of different maturing group of soybean genotypes with respect to different physiological and biochemical indices for higher productivity under variable photoperiods. To achieve the objectives, field experiments were conducted during kharif seasons of 2012 and 2013 at Punjab Agricultural University, Ludhiana. The experiment were laid out in randomised block design with three replications consisting of 15 genotypes to screen for various morpho – physiological traits, yield and yielding attributes in first year. On the basis of results obtained from the first year experimentation, two genotypes from early maturing genotypes and each of three from medium and late maturing genotypes were selected for biochemical analysis. Morpho-physiological parameters viz., leaf area, leaf area index, leaf and stem fresh and dry weight, net photosynthesis, growth efficiency, chlorophyll content, photochemical efficiency and transpiration rate were affected by photoperiods. Under both the photo-periodic conditions, the late maturing group genotypes maintained higher leaf area, biomass accumulation, leaf area index, photosynthetic rate and transpiration rate as compared to medium and early maturing genotypes leading to higher yield. Under longer photoperiod i.e. June sowing showed more metabolic status as compared to shorter photoperiod (July sowing). Nitrogen metabolizing enzymes viz., GOGAT, GS, GDH and NR activity showed varied response in leaf and stem. Highest activity of these enzymes was found in longer photoperiod as compared to shorter photoperiod. Carbon metabolizing enzyme- invertase also showed varied response in podwall and developing seeds. The activity of this enzyme increased in developing seeds and the highest activity was observed in late maturing genotypes. Finally, it can be concluded that for selection of better genotypes under variable photoperiods, the physiological parameters total dry matter, CGR, RGR, photosynthetic rate, chlorophyll content, LAI, SPLW, 100 seed weight, numbers of pods per plant and harvest index should be considered. These parameters were found to have significant positive correlation with seed yield. Of the evaluated 15 diverse maturing genotypes, the early maturing genotypes EC 457161, medium SL 983 and late SL 958 are superior in terms of yield as well as in other morpho-physiological traits. Of all genotype SL 958 performed the best.
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Physiological basis of nitrogen use efficiency in maize (zea maysl.) at various rates of applied nitrogen
(PAU, 2012) Amandeep Kaur; Bedi, Seema
Field and laboratory experiments were conducted at Punjab Agricultural University, Ludhiana during kharifseason in the years 2009 and 2010 respectively to study the physiological basis of nitrogen use efficiency in maize (Zea mays L.) at various rates of applied nitrogen. Six maize genotypes (hybrids and their parents) i.e., long duration PMH1 (parents LM13, LM14) and short duration JH3459 (parents CM143, CM144) were raised under five nitrogen levels viz; recommended (RDN), RDN+25%, RDN+50%, RDN-25% and RDN-50% respectively. Various ecophysiological traits viz; leaf area, leaf area index (LAI), fraction of PAR intercepted by plants (FRI), intercepted photosynthetically active radiation (IPAR), radiation use efficiency (RUE) were significantly improved with the application of nitrogen at higher than the recommended rates in both long and short duration genotypes. Low nitrogen levels increased anthesissilking interval and shortened the duration of grain filling. It also caused a reduction in grain yield and its determinants mainly harvest index, 100-kernel weight, cob weight, above ground biomass, shelling percentage, cob length and diameter, number of kernel rows per cob and number of kernels per cob. The various physiological traits such as plant height, crop growth rate, relative growth rate, dry matter accumulation, root-shoot ratio etc. were significantly increased with the application of 25% and 50% higher nitrogen than the recommended. The applied nitrogendose also affected the content of various biochemical constituents (total soluble sugars, total soluble proteins, total starch content, chlorophyll content as well as the activity of various enzymes viz., nitrate reductase (NR), glutamine synthetase (GS), glutamate synthase (GOGAT) and PEP carboxylase). Path coefficient analysis showed that various traits such as RUE, LAI, FRI, IPAR, GS and NR activity had the maximum positivedirect contribution to grain yield in both set of maize genotypes (long and short duration). Therefore, these traits should be used as target traits to improve maize grain yield at both high and low nitrogen levels. The various quality parameters (starch, proteinand oil) in grains of both long and short duration genotypes were maximum in the treatment RDN+50%. Aminoacid content (total free amino-acids, tryptophan and methionine content) was significantly decreased with the decrease in nitrogen (RDN-25%; RDN-50%) than the recommended. In contrast, there was a decreasing pattern in nitrogen use efficiency (NUE), nitrogen remobilization efficiency (NRE) and nitrogen harvest index (NHI) values with increasing fertilizer rates in both long and short duration genotypes. Hybrids i.e. PMH 1 (long duration) and JH 3459 (short duration) were more responsive to variations in nitrogen supply than their female and male parents. Moreover, the high nitrogen use efficiency for hybrids (PMH1, JH3459) as compared to their parents (LM13, LM14 ; CM143, CM144) was associated with greater PAR interception during the growth period , high radiation use efficiency (RUE), more harvest index (HI), high photosynthetic capacity associated with increased acitivity of PEP carboxylase enzyme and high chlorophyll content in leaves, high nitrogen metabolic efficiency, increased activity of nitrogen metabolism enzymes (nitrate reductase, glutamine synthetase and glutamate synthase) leading to higher nitrogen harvest in dex. Keywords:GOGAT, GS, maize, nitrogen, NR, NUE, PAR, PEP carboxylase, RUE, yield
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Photosynthetic efficiency of wheat genotypes in relation to yield under terminal heat stress
(PAU, 2014) Radhika; Thind, S.K.
To evaluate the sensitivity or tolerance level of 40 wheat genotypes (assembled by CIMMYT and some Punjab cultivars as checks) a laboratory experiment, the two periodic field experiments (2011-12 and 2012 -13) with normal sowing (November 30) and late sowing (December 30) and a pot experiment (2013-14) were conducted. The cell membrane thermo stability supported lesser lipid peroxidation (MDA) and minimal changes in mitochondrial activity (TTC) of heat tolerant genotypes which ultimately increased the survival potential under laboratory conditions after long term (24 hrs) heat shock treatment (40±2°C). Delay in planting under the field conditions caused significant decrease in the source sink activity, photosynthetic efficiency and grain growth parameters besides negative effects of terminal heat stress. The impact of this adversity could be clearly seen in the late maturing genotypes as they were prone to the leaf senescence under the late sown conditions. The studied correlation suggested that net assimilation rate, leaf area index, total chlorophyll, starch, pre-stem reserve mobilization, canopy temperature depression, net photosynthetic rate and transpiration rate were found to be effective traits defining wheat genotypes adapted to production systems prone to high temperature stress at 10 DAA. Early maturing genotypes were less affected while late maturing genotypes were found sensitive and were affected up to much more extent as these were highly dependent upon the reserves for the grain filling with the onset of the terminal heat stress. A significant difference was recorded among the genotypes for various quantity and quality contributing traits. An increase in seed protein content, wet gluten, dry gluten, gluten index and sedimentation value and the decrease in number of grains/ spike, seed weight/spike,1000 grains weight, grain hardness and moisture content was recorded under the late planting conditions. Under the pot conditions the tolerant genotypes had relatively higher and wider growth ratios, photosynthetic efficiency (net photosynthetic rate, stomatal conductance and Rubisco enzyme activity) and grain yield when these were subjected to the heat stress (40±2°C) for 8hrs at anthesis.

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