فلاح

Almond (Prunus dulcis L.) is one of the most important nut crops in Iran. Most almond cultivars and genotypes are self-incompatible. However, research on S-alleles indicates that it is very efficient in cultivar selection. Self-incompatibility in almond is gametophytic and controlled by a single S-locus with multiple codominant alleles. In this study, compatibility relationships among cultivars, “Tuono”, “Shokofeh”, “Sahand” and five improved genotypes “A1.16”, “A9.7”, “A8.39”,“A10.11” and “A230,” was investigated by the PCR of S-alleles. Degenerate primers (PaConsI-F, EM-PC1consRD, EM-PC2consFD, and EM-PC3consRD) were used for amplification of S-alleles. Results showed that only “A10.11” and “A8.39” were completely cross-incompatible, but all of the other studied cultivars and genotypes were cross-compatible. Furthermore, cultivar “Tuono” and genotype “A1.16” had a self-fertility allele.

The rice crop is cold sensitive plant that under cold stress is more decreasing yield.Therefore, knowing defense mechanism of rice crop and low temperature is necessary.In order to, the effects of cold on some morphological and physiological characters oftwo rice (Oryza sativa L.) varieties (Onda and Domsiah) were studied under controltreatment (day/night 28o/25o) and were treated after two weeks with cold stress(day/night 15o/13o). The results showed that dry weight, length of shoot and rootdecreased in both varieties significantly, but the Domsiah variety was more decreased.The amount of chlorophyll a, b and starch content was decreased under stress in twovarieties. However, the amount of decreasing was about 48, 54 and 38 percentagesrelated to control treatment in leaves of the Domsiah variety, respectively. The contentof proline, MDA, soluble sugars were increased in the Domsiah variety in which theamount of increasing of proline and MDA were 62 and 70 percentages respectivelyFructose content in Onda variety was observed about 74% as to control. Results showedthat Onda variety was tolerant than Domsiah variety and as a results was more toleranceto cold stress.

In order to evaluate the response of rice genotypes to salinity stress, 16 rice genotypeswere assessed to 4 salinity levels (0, 4, 8, 12, dS/m) through a split plot experiment basedon completely randomized design at germination stage. Germination percentage,germination rate, length of radicle, length of shoot, radicle dry weight, shoot dry weight,total biomass, and total radicle-shoot weight were measured. Results showed thosegermination percentage and germination rates were decreased by the increase of salinity. It was demonstrated that tolerant varieties had a more germinate. Salinity had a significanteffect on all of the studied traits expect total biomass. Germination rate showed significantcorrelations with germination percentage, radicle length, shoot length, and dry weights ofradicle and shoot (P≤0.01). Dry weight of shoot showed significant correlations withgermination percentage, radicle length and shoot length. Based on germination traits,PSBRC88 and IR58025A/IR60819R were determined as salt tolerant and sensitivevarieties, respectively. Results of this study would help to select for salt tolerant varieties in rice breeding programs.