Classification of wheat genotypes on the basis of morphological and physiological traits in combination with spot blotch resistance under terai sub-Himalayan region

The present study was carried out to evaluate variability among 50 diverse genotypes of wheat (Triticum aestivum L.) for yield attributes and biotic factor like spot blotch during 2018-19 rabi season. Observations were recorded for morpho-phenetic traits, physiological parameter and disease observations of spot blotch (Bipolaris sorokiniana (Sacc.) Shoem) was done at four crop growth stages viz. 85 DAS, 92 DAS, 99 DAS and 106 DAS. The mean value of chlorophyll index (CI) indicated gradual decline of CI with advancement in growth stages. Highest value of AUCIDC was shown by ESWYT-50 (128.33), while the lowest value was exhibited by ESWYT-25 (22.75). Mean value of disease severity in the different growth stages indicated gradual increase in disease severity along with advancement in growth stages. Correlation study among AUDPC, AUCIDC along with three morpho-phenotypic traits revealed significant and positive correlation between AUDPC and AUCIDC. The D2 analysis distributed 50 wheat genotypes into six clusters. The genotypes having lower selection index values were ESWYT-36, ESWYT-40, ESWYT-22, ESWYT-35, ESWYT-18, ESWYT-10, and ESWYT-1, which were also distributed in different divergent clusters as per D2 analysis. Thus, they could be used as spot blotch resistant genotypes with early flowering type along with high yield. All the traits exhibited low PCV and GCV values indicating the presence of common parents in the ancestry of the wheat genotypes.