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2015 - 20183
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Subject: Vegetable Science × End date: 2018 × Start date: 2010 × Type: Thesis × Thesis Type: Ph.D ×
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    ThesisItemOpen Access
    Assessment of genetic diversity in carrot genotypes using morphological, biochemical and molecular markers
    (Punjab Agricultural University, Ludhiana, 2018) Davinder Singh; Dhillon, Tarsem Singh
    The study entitled “Assessment of genetic diversity in carrot genotypes using morphological, biochemical and molecular markers” was carried out at Vegetable Research Farm, Department of Vegetable Science, Punjab Agricultural University, Ludhiana. Eighty one genotypes of carrot were characterized by morphological, biochemical and molecular markers during 2015-16 and 2016-17. Analysis of variance showed significant differences for 19 quantitative traits with respect to treatment, year and treatment x year. Maximum total root yield was obtained from genotypes viz. PC-161, PC-15, PC-43 and PC-103 (red), PCO-30 and PCO-5 (orange) and PCP-2 and PCP-1 (purple). On the basis of morphological diversity, 81 genotypes were distributed into ten clusters. Cluster X was the best for root weight and anthocyanin content, cluster III for days to 1st root harvest and root girth, while dry matter content, total sugar content and carotene content were maximum in cluster V. The highest intra cluster distance has been observed from the cluster VII (162.9), while inter cluster distance was maximum between II and cluster X (43678.5). The cumulative proportion of variation explained by the four PC-axes was 85.12 %. Seventeen polymorphic SSR markers differentiated genotypes into three groups where cluster I consisted of 48 genotypes followed by cluster II with 28 genotypes and cluster III had 5 genotypes. The morpho-biochemical and SSR markers were effective tools to identify closeness among genotypes, so future strategy involves utilizing more SSR markers culled from various linkage mapping could be effectively and efficiently used to fasten the breeding programs and to design trait specific carrot breeding.
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    Mitigation of cold stress in tomato (Solanum lycopersicum L.) through physiological interventions
    (Punjab Agricultural University, Ludhiana, 2017) Meena, Yogendra Kumar; Khurana, Daljit Singh
    To study ameliorate effect of phenolic compounds against low temperature stress in tomato under open field conditions during the winter season of 2014-15 and 2015-16. The cultivar Punjab Ratta comprised the plant material were given foliar application twice, first 15 days after transplanting followed by another spray after a fortnight of different concentrations of phenolic compounds viz., salicylic acid, sulfosalicylic acid, methyl salicylic acid, benzoic acid and acetyl salicylic acid (0.1mM, 0.5mM & 1.0mM) in order to evaluate their effect on morphological, physiological, yield and quality traits. The observations recorded during two years revealed that low temperature significantly reduced the growth biomarkers (plant height, number of branches, number of leaves, shoot and root length, and total biomass of plant, leaf are index, specific leaf area, leaf weight ratio, relative growth rate and net assimilation rate), physiological and biochemicals attributes viz., relative water content, photosynthetic pigments (chlorophyll and carotenoid content), ascorbate peroxidase activity, yield attributes (number of flowers per cluster, number of fruits, fruit weight and fruit yield) and quality parameters (total soluble solid, lycopene, β-carotene and α-tocopherol). On the other hand, low temperature significantly enhanced the specific leaf weight, electrolyte leakage, accumulation of osmoprotectants (proline, total soluble sugar and sucrose), catalase, peroxidise, hydrogen peroxide and lipid peroxidation. However, application of phenolic compounds mitigated cold stress by increasing abovesaid growth, physiological and biochemicals, yield and quality attributes and furthermore by accumulating osmoprotectants, increasing the activity of antioxidant enzymes and reduced the specific leaf weight, electrolyte leakage, hydrogen peroxide and lipid peroxidation. Among all treatments, salicylic acid @ 1.0mM was found to be the most effective to mitigate low temperature stress in tomato.
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    ThesisItemOpen Access
    Optimizing soil matric potential and climate based irrigation scheduling to potato under different establishment methods
    (PAU, 2015) Ahuja, Sanjeev; Khurana, D.S.
    An Investigation under experiment-I was conducted with the objective to determine the most appropriate installation depth of tensiometer with suitable soil matric potential for higher tuber yield and water use efficiency of potato under furrow-ridge irrigation system at Vegetable Research Farm, Punjab Agricultural University, Ludhiana during 2011-12 and 2012-13. Three levels of soil matric suction (S); 20, 35 & 50 kPa at three installation depths (D) of tensiometer; 20, 30 & 40 cm and a control (traditional practice) were replicated thrice in RCBD. The pooled analysis of data showed that treatments S20D20 and S35D20 recorded 86 and 82% higher marketable tuber yield compared to the control. The WUE under S35D20 treatment was upto177% higher than control when data was pooled over two years. Highest dry tuber yield was recorded in S35D20 treatment among all the treatments during both the years. The analysis of pooled data for marketable and graded tuber yield, average tuber weight, discarded percent of tubers, root dry weight, lower content of reducing sugars and higher percent of starch and protein content, plant height at harvest and above ground dry matter accumulation 30, 60 DAP and at harvest also favoured S35D20 and S20D20 treatments. However averaged over two years, WUE and WUEi of S35D20 was more than double as compared to control treatment along with higher marketable tuber yield as 49 % irrigation water was saved. The results revealed that treatment S35D20 was the best treatment for irrigation scheduling in the region. Further, experiment-II was conducted in split plot design with four replications to compare the climatic based irrigation scheduling with S35D20 under ridge-furrow (M1) and bed-furrow planting (M2) system during 2012-13 and 2013-14. Two rows were planted on each bed under furrow-bed planting system. The treatments consisted of five irrigation levels: I1; IWCPE (Irrigation water to cumulative pan evaporation) ratio 1.0, I2; IWCPE ratio 1.25, I3; IWCPE ratio 1.5, I4; S35D20 (tensiometer installed at 20 cm soil depth maintaining SMP of -35 kPa) and I5; control (farmers practice in the region). The ridge-furrow method of planting (M1) showed its advantage over the bed-furrow method of planting (M2) in terms of recording higher WUE, average tuber weight, marketable tuber yield, large and medium sized tuber yield, plant height at 60, 75 DAP and at harvest as well as above ground dry weight accumulation at the time of harvest. Almost three times higher water use efficiency was recorded by S35D20 as compared to control treatment (farmer’s practice) under M1 method of planting. This irrigation treatment was superior in terms of plant height, above ground DMA at 60 DAP and at harvest, graded and marketable tuber yield, starch and protein content and has lower discarded percent of tubers among all other treatments. The results of two experiments suggest that scheduling irrigation based on soil matric potential at -35 kPa SMP with tensiometer installing at soil depth of 20 cm under ridge-furrow irrigation system was better option under North-Western plains of India. Adopting this threshold corresponds to 3 to 4 irrigations of 45 to 45.5 mm each depending on the rainfall during potato growing period. Two separate irrigations of 50 mm each were applied, first as pre-planting irrigation and second irrigation to substantiate emergence. Thus, application of single irrigation two weeks after the complete emergence of crop and remaining 2-3 irrigations at 17 days interval may save irrigation water as compared to the traditional irrigation practice.