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Start date: 2010 × Rating Count: 5 × Thesis Type: M.Sc ×
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    ThesisItemOpen Access
    Horticultural and molecular evaluation of tomato lines for multiple disease resistance
    (Punjab Agricultural University, Ludhiana, 2021) Rane Omkar Harikrishna; Jindal, Salesh Kumar
    Tomato (Solanum lycopersicum L.) can be grown throughout the year but its production is hampered due to attack of several diseases. In tropics and subtropics, tomato leaf curl disease (ToLCD), late blight (LB) and root knot nematode (RKN) are the major diseases, which can cause 90-100 percent losses of yield and quality. Hence, six genes (Ty-1, Ty-2, Ty-3, Ph-2, Ph-3 and Mi-1.2) were pyramided from different parents to accomplish resistance against ToLCD, LB and RKN. In the present investigation, 132 lines of BC2F6 population were screened for resistance to multiple diseases along with horticultural traits. The popular released cultivar ‘Punjab Chhuhara’ was used as a common susceptible control for all the three diseases and resistant controls include Punjab Varkha Bahar-4 for ToLCD, LBR-10 for LB and NR-14 for RKN. Natural, artificial and marker aided screening were carried out for identification of disease resistant lines. In 2019-20, horticultural evaluation of advance breeding lines along with screening for multiple disease resistance under natural and artificial conditions was done. During 2020-21, marker assisted screening against diseases was employed. Out of 132 lines screened, 5 lines viz. PDRT-104, PDRT-118, PDRT-122, PDRT124 and PDRT-125 were found to be resistant against all the three diseases viz. ToLCD, LB and RKN along with better horticultural traits. The lines namely PDRT-145 and PDRT-154 possessing resistance against ToLCD and RKN and the line PDRT-1 possessing resistance against LB and RKN. Among these lines, PDRT-104 and PDRT-122 were found to be possessing all the six genes (Ty-1, Ty-2, Ty-3, Ph-2, Ph-3 and Mi-1.2) with average yield of 3.07 and 3.44 kg/plant, respectively. Whereas, the lines PDRT-124 and PDRT-125 were found to possesses five genes (Ty-1, Ty-2, Ty-3, Ph-2 and Mi-1.2) with average yield of 3.04 and 2.78 kg/plant, respectively. The multiple disease resistant lines found in the present study could be evaluated at multi-site for their commercial exploitation and can also be considered as potential candidates in resistance breeding programmes of tomato crop.
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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