Molecular identification and genetic relationships among coffee species (Coffea L.) inferred from ISSR and SRAP marker analyses

The identification and genetic relationships of 23 coffee species and one coffee-related species Canthium diccocum were studied using ISSR and SRAP markers. The average polymorphism information content of SRAP primers (0.81) was lower than ISSR primers (0.86), whereas the average resolving power of the SRAP primers (9.74) is higher than the ISSR primers (8.64). The genetic similarity among the species ranged from 0.30 to 0.89 using ISSR and 0.11 to 0.90 using SRAP marker systems. Based on marker analysis, all twenty three coffee species were clustered into two major groups. Both the markers amplified species-specific fragments and are useful in genetic diversity analysis of coffee

Genetic diversity among ethiopian coffee (Coffea Arabica L.) collections available in indian gene bank using sequence related amplified polymorphism markers

The South-Western highlands of Ethiopia are considered to be the centre of origin and diversity of the arabica coffee, Coffea arabica. More than 80 accessions of arabica coffee collected from Ethiopia are avail-able in Indian gene bank. However, the genetic diversity of these accessions is not studied in detail. In the present study, genetic diversity analysis of 48 accessions collected from eight provinces of Ethiopia was car-ried out using Sequence-related amplified Polymorphism (SRAP) marker. Among the thirty two SRAP primer combinations tested, 14 primer pairs were polymorphic and generated 203 distinct fragments. The number of fragments ranged from 7 to 21 with a mean of 14.5 fragments per primer combination. Of the total 203 ampli-fied fragments, 182 (89.65%) were polymorphic and the percent of polymorphism ranged from 53.84% to a maximum of 100% using different primers. The average resolving power (Rp) and average polymorphism information content (PIC) of the 14 SRAP primer combinations was 14.31 and 0.648 respectively. A total of 13 rare alleles were obtained from SRAP assays, of which six rare alleles were obtained from the accessions collected from Shoa province.The UPGMA clustering algorithm from SRAP analysis grouped the 48 coffee accessions into two major clusters. The accessions collected from particular province clustered together which could be attributed to the substantial gene flow between adjacent population and the influence of geographical origin on genetic diver-sity. The study demonstrated the existence of substantial genetic variation in Ethiopian germplasm which could be utilized in coffee germplasm conservation and improvement program

Estimates of Genetic Variability, Association Studies and Per se Performance of Tomato Genotypes for Growth and Yield Parameters Under Drought Stress Conditions

Aims: Drought tolerance is a complex phenomenon, influenced by the coordinated activity of many genes. Breeding for drought tolerance is the need for contemporary research under the present climate change scenario. Further, the estimates of variability and degree of association among the traits would facilitate the selection for yield under drought conditions as it is highly influenced by environmental factors. This study aimed for the enhancement of selection capacity for drought stress tolerance in tomato based on the measures of genetic variability parameters and extent of association among traits which in turn used to identify drought tolerant genotypes. Methodology: The experiment was conducted with 39 tomato genotypes with 2 replications under normal and drought stress condition (15 days irrigation interval) following a Randomized Block Design during summer, 2020 at Department of Biotechnology and Crop Improvement, Kittur Rani Channamma College of Horticulture, Arabhavi. Results: High heritability along with moderate to high GAM was recorded for all the characters under study in both control and drought stress condition, indicating predominance of additive gene action for these traits. Yield per plant had positive and strong association with plant height, stem girth, number of primary branches, number of fruits per plant and average fruit weight. Further, path analysis revealed high desirable direct effect of average fruit weight and number of fruits per plant on yield per plant. Thus, there is ample of scope for improving these traits through selection. The genotypes viz., EC-634394, EC-638519 and Kashi Anupama shown superior performance for yield along with other yield attributing traits and also exhibited less percent reduction in these traits under drought condition

Screening of China Aster [Callistephus chinensis (L.)] Genotypes and F1 Hybrids against Alternaria Leaf Spot Disease

Leaf spot disease caused by Alternaria alternata (Fr.) Keissler is a threat of China aster cultivation and is capable of causing yield losses in all production regions. The experiment was undertaken to screen genotypes and F1 hybrids which would be helpful in developing Alternaria leaf spot resistance varieties in later years. AAC-1 was found to be resistant against Alternaria leaf spot in both field and control conditions. In natural disease pressure, Arka Kamini, Arka Shashank and Arka Poornima recorded to be moderately susceptible, susceptible and highly susceptible to Alternaria leaf spot, respectively. However, in artificially inoculated condition, Arka Kamini showed susceptible reaction. Among F1 hybrids, AAC-1 x Arka Kamini and Arka Kamini x AAC-1 showed moderately resistant reaction; AAC-1 x Arka Poornima, AAC-1 x Arka Shashank, Arka Poornima x AAC-1, Arka Shashank x AAC-1 showed moderately susceptible disease reaction for Alternaria leaf spot