Genetic evaluation of Jatropha backcross hybrid clones (BC4F1) for yield and oil quality.

Jatropha curcas is a tropical species that has been recognized as a promising biodiesel plant. During 2018-2021, researchers at Forest College and Research Institute, Mettupalayam, elicited information on Jatropha's biochemical characteristics, growth performance, variability, and association studies for biometric variables using five backcross (BC4F1) hybrid clones of Jatropha with a control variety TNMC 7. In terms of seed yield, two hybrid clones, CJH 13 (1,218.60 g) and CJH 12 (1,034.40 g), outperformed the other hybrid clones. The seed oil content was higher in CJH 5 (34.19%). The seed oil content had moderate PCV (16.49%) and GCV (16.39%) values, as well as high heritability (99%) and genetic advance (33.56%) as a percentage of the mean. The number of fruits per bunch (0.845 and 0.850) and the number of bunches per branch (0.771 and 0.788) had significant positive phenotypic and genotypic correlations with seed yield, respectively. The iodine numbers, cetane numbers, and saponification values of all hybrid clones were acceptable and satisfactory and were in good compliance with Indian and international biodiesel standards.

Variation in biochemical, physiological and ecophysiological traits among the teak (Tectona grandis Linn. f) seed sources of India.

Teak being an iconic timber species the studies on its physiological and biochemical traits are very limited in India and worldwide. As a result, the current study aimed to assess biochemical parameters such as chlorophyll a, chlorophyll b, total chlorophyll, carotenoids, chlorophyll ab ratio, proline content, and peroxidase activity, along with physiological parameters such as Chlorophyll stability index, relative water content, and leaf area, as well as ecophysiological traits such as net photosynthetic rate (Pn), stomatal conductance (Gs), intercellular CO2 concentration (Ci), transpiration rate (Tr), Leaf temperature, intrinsic water-use efficiency (iWUE), instantaneous water use efficiency and intrinsic carboxylation efficiency of thirty teak seed sources collected from different states of India. FCRITK 19, FCRITK 21, FCRITK 25, FCRITK 29, and FCRITK 05 were reported to have a greater photosynthetic rate (> 17 µmol m-2 s-1) coupled with a relative water content of more than 50% and a chlorophyll stability index of more than 60%, which could be used in a future genetic improvement programme. Correlation analysis indicated that water use efficiency was found to be strongly but negatively correlated with transpiration rate (-0.601) and stomatal conductance (-0.910). The proline content had a substantial positive correlation with the chlorophyll stability index (0.890), signifying that they are associated with abiotic stress conditions. Cluster analysis was attempted to discriminate the sources based on biochemical, physiological and ecophysiological traits. Eleven sources (FCRITK 25, FCRITK 27, FCRITK 29, FCRITK 14, FCRITK 30, FCRITK 16, FCRITK 05, FCRITK 13, FCRITK 02, FCRITK 17 and FCRITK 15) exhibited superior performance compared to rest of the sources.

Molecular characterization of Jatropha genetic resources through inter-simple sequence repeat (ISSR) markers.

The genetic diversity among eight Jatropha species and three Jatropha curcas accessions were analyzed using ISSR-PCR. Nine ISSR primers generated reproducible amplification banding pattern of 61 polymorphic bands out of 64 scored accounting for 98.14% polymorphism across the species. The ISSR primers viz., I1, I2, I3, I4, I5, I6, I7 and I10 generated 100% polymorphic patterns. Jaccard's coefficient of similarity varied from 0.346 to 0.807, indicative of high level of genetic variation among the genotypes studied. The UPGMA cluster analysis indicated three distinct clusters, one comprising all accessions of J. curcas L (TNMJ1, TNMJ 22 and TNMJ 23), while second included four species viz., J. tanjorensis J. L. Ellis et Saroja., J. gossypifolia L., J. podagrica Hook and J. maheshwarii Subrum and M.P. Nayer and the third cluster included another four species viz., J. villosa Wight J. multifida L., J. integerrima Jacq and J. glandulifera Roxb. The overall grouping pattern of clustering corresponds well with principal component analysis (PCA) confirming patterns of genetic diversity observed among the species. So far, there are no reports on the molecular diversity of the Jatropha species through ISSR marker. This study provides valid guidelines for collection, conservation and characterization of Jatropha genetic resources and also for further breeding programme towards biodiesel production.