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Subject: Agricultural Meteorology × Author: Boruah, Angita × End date: 2023 × Start date: 2020 ×
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    ThesisItemOpen Access
    EVALUATION OF FINGER MILLET GENOTYPES AS CLIMATE SMART CROP UNDER THE AGROCLIMATE OF JORHAT
    (2023) Boruah, Angita; Deka,Rajib Lochan
    A field experiment was conducted during kharif, 2022-23 at Instructional cum Research (ICR) Farm of Assam Agricultural University, Jorhat to study crop weather relationship and genetic diversity among five finger millet genotypes viz. Gossaigaon Maruadhan (V1), FMAVT 4001 (V2), FMAVT 4006 (V3), FMAVT 4007 (V4) and FMAVT 4012 (V5) grown under three microclimatic regimes: 6th August (D1), 22nd August (D2) and 6th September (D3), following split plot design with three replications. The weekly mean maximum (Tmax) and minimum temperature (Tmin), rainfall (RF), morning (RH-I) and evening relative humidity (RH-II), bright sunshine hours (BSSH), pan evaporation (EVP) and wind speed (WS) ranged from 22.1ºC to 34.9ºC, 7.9ºC to 25.6ºC, 0 to 104.4 mm, 91 to 100%, 51 to 85%, 1.9 to 9 hours, 1.1 to 3.8 mm and 0.8 to 3.1 kmph respectively during the period of experimentation. Biometric observations, viz. plant height, leaf area index (LAI), biomass, number of effective tillers/m2, number of earheads/m2, number of fingers per earhead, finger length, test weight, grain and straw yield were recorded periodically during entire growing season and at the time of harvest. Soil temperature at 10 cm depth was recorded daily, soil moisture at 15 days interval and incident, reflected and transmitted photosynthetically active radiation (PAR) at 7 days interval were also recorded during the experimental period. Results revealed that LAI, plant height and biomass at all the growth stages differed significantly under different microclimatic regimes with highest values recorded in the early sown (D1) crop. Accumulated agroclimatic indices such as GDD (growing degree days), HTU (heliothermal units) and PTU (photothermal units) decreased gradually with successive delay in sowing time with highest value being recorded under D1. Yield attributes and grain yield were found highest in early sown crop (D1) as compared to late sown crops. The vegetative phase of the first sown (D1) crop was exposed to comparatively higher soil temperature regime as compared to late sown crops (D2 and D3). The crop sown on 6th August (D3) had the highest PAR interception rate (72.6%). Among the genotypes, Gossaigaon Maruadhan (V1) was found to be superior with respect to growth parameters and yield (17.94 q/ha). Correlation analysis revealed that yield attributes and yield were significantly positively correlated with Tmax, Tmin, and WS whereas the correlation was negative and significant with RHI during all growth phases. EVP and BSSH had significant positive association with yield and yield attributes in all the phases of the crop growth except during reproductive phase. Yield predictive models were developed by utilizing step-wise multiple regression method using mean and accumulated agroclimatic indices during different pheno phases and entire period of crop growth. The most efficient yield predictive model among mean phasic meteorological parameters was found with Tmin during vegetative phase with highest coefficient of determination (R2=0.932) irrespective of varieties. While, among the accumulated meteorological indices, the best models were found for PTU (R2=0.932) and RF (R2=0.932) during vegetative phase and entire growing period respectively. For genetic diversity analysis, 20 RAPD primers were used out of which 7 were found to be polymorphic. These markers amplified 46 alleles with an average of 4.6 alleles per marker. Genetic relationship among finger millet genotypes were found out on the basis of pairwise Jaccard’s similarity coefficient whose value ranged from 0 to 0.6 with an average of 0.295. Cluster analysis by UPGMA method grouped 20 samples into two major clusters, each further sub-divided into two sub-clusters. Cluster A comprised of 15 samples while cluster B had only 5 samples. All the treatment combinations of varieties V2, V3, V4 and V5 were grouped in cluster A, while treatment combinations of V1 were grouped in cluster B which indicates their genetic dissimilarity. These results indicated that different plant characters exhibiting strong positive genotypic and phenotypic correlation with grain yield can be used for development of high yielding genotypes of finger millet crop.