Muharrem Kaya

Interaction between seed size and NaCl on germination and early seedling growth of some Turkish cultivars of chickpea (Cicer arietinum L.)

Chickpea is an important food legume crop of Turkey and is largely grown for human consumption on low moisture or salt-affected soils. The objective of the study was to find the effects of NaCl stress at electrical conductivities of 4.5, 8.6, 12.7 and 16.3 dS/m and seed sizes (7, 8 and 9 mm) on germination and early seedling growth of three popular chickpea cultivars (AKN-97, Gokce and Uzunlu-99). Mean frequency of germination, germination time, germination index, root length, shoot length and seedling fresh weight showed seed size-dependent responses of cultivars to salt stress. In general, small seeds germinated and grew more rapidly compared to medium and large seeds of the same cultivars against all levels of salt stress, with the best results in cultivar Uzunlu-99. No effect of NaCl treatments was observed on frequency of germination; however, a drastic decrease in early seedling growth was recorded at increased NaCl concentrations. Regression analysis results showed a significantly positive relationship (P<0.01) between seed size and mean germination time, whereas a significantly negative relationship was recorded between seed size and germination index, root length, shoot length. Moreover, linear regression values apparently confirmed that increased seed size in each cultivar affected decreased germination index, root and shoot lengths with enhanced mean germination time. Thus, it was concluded that the use of small seeds could considerably reduce the production costs of chickpea in salt-affected soils.

Adventitious Shoot Regeneration and Micropropagation in Calendula officinalis L.

Hypocotyl, cotyledon and cotyledonary node explants of Calendula officinalis L were cultured on Murashige and Skoog (MS) media supplemented with various concentrations of thidiazuron (TDZ), kinetin (KIN), α-naphthaleneacetic acid (NAA) and indole-3-butyric acid (IBA) to induce adventitious shoot regeneration and micropropagation. The highest frequency of adventitious shoot regeneration was achieved from hypocotyl and cotyledon explants on MS media supplemented with 0.75 mg dm−3 TDZ and either 0.25 or 0.50 mg dm−3 IBA. Efficient in vitro clonal propagation was also induced from cotyledonary nodes on a range of media supplemented with 0.75 mg dm−3 TDZ and 0.05 mg dm−3 NAA or 2 mg dm−3 KIN and 1 mg dm−3 NAA. Regenerated shoots were excised and rooted in MS medium supplemented with 1 mg dm−3 NAA. The rooted plantlets were finally transferred to pots.

Effect of age on somatic embryogenesis from immature zygotic embryos of 5 Turkish triticale genotypes

Triticale is an important cereal crop grown throughout the world. The study reports somatic embryogenesis from immature zygotic embryos of 5 Turkish triticale genotypes. The explants were initially cultured on MS medium supplemented with 2 mg dm-3 2,4-D, 500 mg dm-3 glutamine, 100 mg dm-3 casein hydrolysate, 2% sucrose and 7% agar for two weeks in the dark. The temperature was maintained at 24±2oC. Thereafter, the developing embryogenic calli were transferred to MS medium without 2,4-D to achieve embryogenesis under light intensity of 30 000 lux in 16 h light 8 h dark photoperiod at 24±2oC for 2 weeks. The developing somatic embryos were then transferred to MS medium to mature them and obtain plantlets. The highest number of 9.63 somatic embryos per explant were recorded for genotype LAD388 from 14 - 16 days old explants. The experiment clearly established that 14 - 16 days old explants were superior compared to 17 - 19 days old explants in terms of number of somatic embryos per explant. The matured plantlets were acclimatised in the greenhouse on organic matter rich soil mix contained in pots.

Tillage impacts on organic matter and plant nutrients in a loam soil of dryland in Turkey

Tillage operations for different soils, sites and agroclimatic conditions can show different effects. We have studied for 3 years (2001-2003) the effects of three tillage systems on soil organic matter (OM) and nutrition of crops, in (Helianthus annuus L.) - barley (Hordeum vulgare L.) - Hungarian vetch (Vicia pannonica Crantz)+triticale mixture rotation, established in a loam soil (typic Xerofluvent) of passage zone between coastal belt and the continental climate of Central Anatolia in Turkey. Tillage treatments were chisel ploughing (C); chisel ploughing+ disc harrowing (CD) and chisel ploughing+combine harrowing (CH). Crops were not fertilized. Soil samples taken from 0-20 cm depths at four different periods of the experiment were used for OM and available nutrients (P, K, Fe, Zn). Plant nutrient analysis (N, P, K, Fe, Zn) were conducted on sunflower and Hungarian vetch+triticale samples at harvesting. In tillage treatments, there were no significant differences either for OM and available nutrients in soil depth studied nor nutrient contents of plants. Accordingly nutrient uptakes of plants depend on OM and available nutrient contents of soil, it seems that the mineralization rate of OM was lower in C treatment. It is concluded that the lack of clear differences could be associated with low OM content in relation to xeric soil moisture regime of experimental soil and the short-term of the experiment.