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2017 - 20202
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Author: Sukhdeep Kaur × Start date: 2012 × Thesis Type: M.Sc ×
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    ThesisItemOpen Access
    Identification of quantitative traits loci (QTLs) for popping traits and kernel size in maize
    (Punjab Agricultural University, Ludhiana, 2020) Sukhdeep Kaur; Rakshit, Sujay
    Popping traits play an important role in the utilization of popcorn. In this study, the F8 RILs population derived from HKI PC4B (Popcorn) × CML 269 (Normal corn) was characterized for seed and popping traits, and sufficient genetic variability was observed in the RILs and the parents for target traits. The best performing RIL(s) in specific environments like RL4, RL51, RL73 were identified using AMMI analysis. A few RILs were found to be superior to those of parents representing their possible use in popcorn breeding. QTL mapping (CIM algorithms) identified a total of 15 QTLs. Out of these QTLs, five QTLs for traits TW, PEV, PPand FV were mapped consistently across the environments on chr 3, 5, 6 and 9, respectively (R2 16.60 – 29.50 %). A total of 10 QTLs identified were environment specific. Two QTLs each for TW, PEV, PP; one QTL for FV were reported on chr 1, 2, 4, 7and 8, respectively. Based on the average values of the traits, three more QTLs were identified for PP, FV and PEV on chr 3 and 1 (R2 4.71 – 11.06 %). MetaQTL approach integrated QTLs from the earlier studies using BioMercator v4.2. A total of 10 metaQTLs were identified and 229 genes were shortlisted in these regions on expression basis (nineteen genes selected using KEGG pathways). The four metaQTLs were considered important for popping traits having 5-8 QTLs clustered in regions. The QTLs for PEV (two) and seven metaQTLs for traits PP, TW, PEV, FS were observed at chr 1, earlier also QTLs and metaQTLs were reported on chr 1. Therefore considered as an important region in enhancement of popping traits
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    Ovipositional preference and biochemical interaction of whitefly, Bemisia tabaci (Gennadius) with Gossypium species
    (Punjab Agricultural University, Ludhiana, 2017) Sukhdeep Kaur; Pandher, Suneet
    The present investigation, “Ovipositional preference and biochemical interaction of whitefly Bemisia tabaci (Gennadius) with Gossypium species” was conducted at Punjab Agricultural University Regional Research Station, Faridkot during the year 2016-2017 with three cultivars of Gossypium arboreum and G. hirsutum under multiple and no choice conditions. The results showed significant difference among Gossypium species in terms of settling of whitefly adults and fecundity per unit area. The maximum number of adults per leaf was observed on G. hirsutum var. F 2228 followed by G. arboreum FMDH 9 and FDK 124.Whitefly preferred G. arboreum var. FMDH 9 for oviposition as indicated by results followed by G. hirsutum var. F 2228, significantly different from each other. The minimum number of eggs was observed on G. arboreum var. FDK 124. The trichome density of 13.67 per five mm diameter leaf disc was the highest on the F 2228. Development time on FDK 124 was 19.79 days whereas in case of F 2228, it was 15.5 days. In the second experiment on insecticide induced resurgence, studies indicated that decline in predator population led to upsurge in Bemisia incidence for short period followed by little decline. This decline probably corresponded to eventual reestablishment of natural enemies depending on the persistence of the insecticide in the environment. Total sugars in Fipronil 5 SC treatments were significantly different at different days after spraying as compared to sampling done before first spray and corresponded with maximum resurgence of whitefly in these plots. Increase in total sugars was found in other treatments also with lesser per cent of resurgence but increase was not significantly different from initial sampling. Further, the surveys were conducted in the cotton growing areas of districts Faridkot and Muktsar at fortnightly interval from July 2016 to April 2017. Nearly thirty weed species belonging to different families were abundantly found during cotton season and off season. Ten weed species exhibiting variable symptoms showed positive results by molecular diagnostic technique (Polymerase chain reaction).The six samples were asymptomatic and also carrier of virus during off season. Two weed species Abutilon theophrasti and Achyranthes aspera having nymphs was not the carrier of virus. Twelve species of weeds neither having nymphs nor the virus, were regarded as the casual hosts of whitefly. Among the three weeds Verbesina encelioides, Solanum nigrum and A. theophrasti the total life cycle of male and female of whitefly was highest on Abutilon theophrasti which might be due to longer egg incubation period, first instar duration and adult female longevity.