Iranian Journal of Genetics and Plant Breeding
Volume:2 Issue: 2, Oct 2013

Sesame is an important oilseed crop in India. To determine potential traits and selection criteria for yield improvement, ninety sesame (Sesamum indicum L.) genotypes were studied in a randomized complete block design with three replications. The data collected on 13 characters were subjected to three different analyses. In variability analysis, high heritability was accompanied by a high genetic advance and a high genotypic coefficient of variation (GCV) for capsule numbers, biomass yield, harvest index and seed yield. In correlation analysis, biomass yield, capsule number and harvest index showed a significant positive correlation among them and with seed yield. In path analysis, reproductive period was the highest direct contributor, while capsule number was the highest indirect contributor via primary branches. The indirect effect of days to maturity was negative via primary branches and positive via biomass yield per plant. Plant height had a direct effect and an indirect effect via biomass yield and harvest index. Biomass yield and harvest index showed a substantial direct effect on seed yield. Therefore, plant height, biomass yield, days to maturity and harvest index should be used in selection, while care should be taken for the handling of reproductive period and capsules per plant in breeding programmes to increase sesame yield.

This research was carried out to evaluate the effect of drought stress on grain yield and qualitative traits in some Iranian landraces of confectionary sunflower. Fifty six confectionary sunflower landraces were evaluated using three different water treatment conditions with three separate rectangular 7 × 8 lattice design with two replications. Irrigation treatments were as follows optimum irrigation، moderate and severe drought stress، where irrigation was carried out after the depletion of 50%، 70% and 90% of available water، respectively. The results of combined analyses showed that the main effect of irrigation treatments، genotypes and interactions between genotype and irrigation treatments was significant on oil and protein percentages، grain، oil and protein yield. The highest grain oil and protein yield were obtained from “Anghane 4” under the optimum irrigation condition. In contrast، in moderate and severe stresses، “Garaghoz 1” and “Salmas-Sadaghian” produced higher grain، oil and protein yield than other landraces. Based on the stress tolerance index (STI) and geometric mean productivity (GMP) indices، landraces 2، 7 and 12 were tolerant to drought stress، while landraces 36 and 37 with the lowest STI and GMP were sensitive to drought stress.

Spinach (Spinacia oleracea L.) is an economically important leafy vegetable crop in many countries. This is the first case study of using SRAP markers to analyze genetic diversity of Iranian spinach accessions. Eight SRAP primer combinations generated 88 scorable bands ranging from 50 to 1000 bp، among which 73 were polymorphic، with an average of 82. 9 polymorphic bands per primer combination and average polymorphism information content (PIC) of 0. 35. Based on the analysis of SRAP data، a similarity matrix was calculated according to the Dice coefficient. Similarity dendrogram was constructed using UPGMA algoritm. Cophenetic correlation between ultrametric similarities of tree and similarity matrix was found to be high (r=0. 85، P < 0. 0001)، suggesting that the cluster analysis strongly represents the dissimilarity matrix. According to the UPGMA dendrogram، the spinach accessions clustered into two groups. This preliminary study demonstrated that SRAP markers are effective for evaluating genetic diversity between and within spinach accessions.

In order to identify drought tolerant chickpea genotypes، an experiment was conducted in the west of Iran، during 2007-2009 cropping seasons. Several selection indices were used to illustrate genotypic differences in response to drought stress. The results of combined analysis of variance showed that year، genotype، stress conditions and their interaction effects were highly significant. Correlation analysis between indices revealed that the yield index (YI)، stress tolerance index (STI)، geometric mean productivity (GMP) and mean productivity (MP) were correlated to grain yield and together in three years، indicating that they can be used as an alternative to each other for selecting drought tolerant genotypes in both stress and non-stress conditions. Consequently، GGE biplot showed that most ideal genotypes for rainfed conditions were genotypes G6 and G15. In conclusion، the identification of these chickpea genotypes with high yield and stability performance under unpredictable environments and high tolerance to drought stress conditions can help breeding programs in future.

Catharanthus roseus L. is an important medicinal plant producing several terpenoid indole alkaloids (TIAs) such as vincristine and vinblastine secondary metabolites with anticancer activity. The TIAs biosynthetic pathways are affected by biotic and abiotic stresses. In this study the effect of drought (7 days)، salinity (150 mM NaCl)، foliar spray of salicylic acid (10-5 M) and salicylic acid in combination with drought and salinity were investigated separately on the expression of desacetoxyvindoline- 4-hydroxylase D4H and deacetylvindoline 4-O-acetyl transferase DAT، two late vincristine and vinblastine biosynthetic pathway genes. RNA samples were extracted from leaves and cDNAs were synthesized from all samples and used for analysis in Real time PCR. Data analysis based on Ct curves showed that the expression of these genes increased by the application of abiotic stresses. The maximum increases in the mRNA levels of D4H and DAT genes (537% and 440%، respectively) were noted in plants exposed to drought stress in comparison to the control condition. Also، the results showed that the effects of salinity، drought + salicylic acid and salinity + salicylic acid stresses were positive on the increase of D4H and DAT genes expression in comparison to the control plants. Salicylic acid treatment caused a slightly higher gene expression than in control and other treatments. Therefore، it can be concluded that the application of abiotic stresses has a significant role in increasing the expression of genes involved in the biosynthetic pathway of vincristine and vinblastine alkaloids.

Lactuca sativa is widely used as a leafy vegetable belonging to the Asteraceae family. Cotyledonary leaves of in vitro lettuce seedlings were transformed by plasmids containing the GCHI gene. Also the effects of number of days of pre-cultivation and co-cultivation of explants were examined on the transformation frequency. After co-cultivation، the explants were transferred onto the regeneration medium containing 200 mg/l ceftriaxone and 20 mg/l kanamycin. The best callogenesis was obtained in the MS medium containing 0. 05 mg/l NAA and 0. 4 mg/l BAP. Shoot regeneration was achieved after transferring the calli onto the MS medium containing 0. 05 mg/l NAA and 0. 4 mg/l BAP. Finally، the shoots were rooted on the MS medium without growth regulators. A PCR analysis of the genomic DNA confirmed the presence of GCHI genes in both T0 and T1 plants. PCR analysis of T0 plants revealed that 10 out of 52 plants were positive for the GCHI gene. The transformation frequency was 19%.