Banana is a fruit crop which has high demand in Ethiopia, but its production is constrained by lack of disease free planting material with conventional propagation methods. For shoot initiation, shoot tip explants were cultured on MS medium supplemented with 0.5, 1.0, 1.5 and 2.0 mg/L BAP. Similarly, MS medium supplemented with BAP at 1.0, 1.5, 2.0 mg/L in combination with IBA at 0.25 and 0.50 mg/L were used for shoot multiplication. Half- strength MS medium augmented with IBA at 1.0, 2.0, 3.0 and 4.0 mg/l were used for root induction. MS medium without PGRs were used as controls. Finally, hardening of the in vitro derived plantlets was carried out in green house both in the primary and secondary acclimatization stages. Results showed that the highest shoot initiation percent (93.40%), highest mean number of shoots per explant (4.67) and lesser day for shoot induction (11.00) were observed in explant cultured on MS + 1.0 mg/L BAP. With shoot multiplication, highest shooting percent (92.60%), maximum number of shoots (7.67) and highest shoot length (5.27 cm) were recorded on MS + 1.5 mg/L BAP + 0.5 mg/L IBA. The highest rooting percent (93.40%), maximum root number per shoot (7.67) and highest root length (11.00 cm) were found on a half strength MS medium + 2.0 mg/L IBA. The survival rate of plantlets were 96.00% in coco peat substrate in primary acclimatization and 97.92% in forest soil, sand and manure substrates mixed at 3:2:1 ratio in secondary acclimatization. Overall, the result showed that the PGRs type, concentrations and combinations used are effective for mass propagation of banana variety studied in this experiment.

Star Ruby is the main grapefruit (Citrus paradisi) variety grown in Turkey; however, small fruit size is a common problem in ‘Star Ruby’ grapefruit. Fruit size is a decisive external quality parameter in citrus at the marketing of fresh citrus fruits. Fruit size can be enhanced by several techniques such as girdling and thinning. Various plant growth regulators are known to affect the growth and size of citrus fruit. The objective of the present study was to observe the effects of 2,4 dichlorophenoxypropionic acid-p (2,4-DP-P) on the fruit size, yield and quality of Star Ruby from 20-year-old trees budded on sour orange rootstock in Adana, Turkey in 2007. Four concentrations (50, 100, 150 and 300 ppm) of 2,4-DP-P were applied 8 weeks after anthesis during physiological fruit drop when the mean fruit diameter was 13-15 mm. The results indicated that the application of 2,4-DP-P increased the fruit size of Star Ruby grapefruit without reducing yield. The application had a significant effect on fruit yield except for trees treated with 50 ppm 2,4-DP-P. Compared with the control trees, applications of 2,4-DP-P increased the number of large, commercially valuable Star Ruby (>93 mm, 89-93 mm and 84-89 mm). No effects were determined on fruit internal quality parameters. Thus, the results of the present study revealed that 2,4-DP-P can be used to improve the fruit size of Star Ruby fruitlets during the June drop.

Banana is a fruit crop which has high demand in Ethiopia, but its production is constrained by lack of disease free planting material with conventional propagation methods. For shoot initiation, shoot tip explants were cultured on MS medium supplemented with 0.5, 1.0, 1.5 and 2.0 mg/L BAP. Similarly, MS medium supplemented with BAP at 1.0, 1.5, 2.0 mg/L in combination with IBA at 0.25 and 0.50 mg/L were used for shoot multiplication. Half- strength MS medium augmented with IBA at 1.0, 2.0, 3.0 and 4.0 mg/l were used for root induction. MS medium without PGRs were used as controls. Finally, hardening of the in vitro derived plantlets was carried out in green house both in the primary and secondary acclimatization stages. Results showed that the highest shoot initiation percent (93.40%), highest mean number of shoots per explant (4.67) and lesser day for shoot induction (11.00) were observed in explant cultured on MS + 1.0 mg/L BAP. With shoot multiplication, highest shooting percent (92.60%), maximum number of shoots (7.67) and highest shoot length (5.27 cm) were recorded on MS + 1.5 mg/L BAP + 0.5 mg/L IBA. The highest rooting percent (93.40%), maximum root number per shoot (7.67) and highest root length (11.00 cm) were found on a half strength MS medium + 2.0 mg/L IBA. The survival rate of plantlets were 96.00% in coco peat substrate in primary acclimatization and 97.92% in forest soil, sand and manure substrates mixed at 3:2:1 ratio in secondary acclimatization. Overall, the result showed that the PGRs type, concentrations and combinations used are effective for mass propagation of banana variety studied in this experiment.

In agricultural production, one of the limiting factors on plant growth and yield is soil salinity. The plant growth regulators are of considerable importance in alleviating the negative effect of salt stress. The study was carried out to determine the effects of salicylic (SA) and gibberellic acid (GA3) on the growth and some physiological characters in canola (Brassica napus L.) under salinity conditions in greenhouse. For this purpose, a factorial experiment set up as completely randomized design was conducted with three levels of SA (0, 0.5 and 1 mM) and GA3 (0, 50 and 100 mg l-1) and four levels of NaCl (0, 50, 100 and 150 mM) with three replications. In the study, leaf area, plant height, electrolyte leakage, chlorophyll content and the loss of leaf turgor were investigated. Salt treatments reduced significantly all of the considered parameters, compared with the control. Salinity caused a significant reduction of 63 and 67%in plant height and leaf area, respectively, as compared to the control plants. On the contrary, electrolyte leakage was markedly increased (six-fold) with increasing NaCl levels. Gibberellic acid increased significantly plant height and reduced the loss of leaf turgor, without a significant improve in other parameters. The results indicated that application of SA and GA3 to salinity stressed plants did not significantly affect canola vegetative growth. However, GA3 caused a partial decrease in the adverse effect of salinity.

Development of an efficient plant regeneration protocol is essential for vegetable crop advancement by biotechnological methods. In this study, regeneration protocols of four pepper lines of different pepper types were optimized. Different protocols for organogenesis were investigated in regeneration experiments. Optimum plant regeneration was obtained in different combinations of 6-Benzylaminopurine (BAP) and Indole-3-acetic acid (IAA) in organogenesis assays. In organogenesis experiment, the highest shoot development was determined as 80% from hypocotyl explant of Demre pepper in 4 mg L-1 BA+0.5 mg L-1 IAA, 80% from hypocotyl explant of Charleston pepper in 3 mg L-1 BA+0.5 mg L-1 IAA, 80% from hypocotyl explant of capia pepper in 5 mg L-1 BA+0.5 mg L-1 and 84% from hypocotyl explant of bell pepper in 5 mg L-1 BA+0.5 mg L-1 IAA. Afterward, shoots were rooted and whole plants were obtained.

Development of an efficient plant regeneration protocol is essential for vegetable crop advancement by biotechnological methods. In this study, regeneration protocols of four pepper lines of different pepper types were optimized. Different protocols for organogenesis were investigated in regeneration experiments. Optimum plant regeneration was obtained in different combinations of 6-Benzylaminopurine (BAP) and Indole-3-acetic acid (IAA) in organogenesis assays. In organogenesis experiment, the highest shoot development was determined as 80% from hypocotyl explant of Demre pepper in 4 mg L-1 BA+0.5 mg L-1 IAA, 80% from hypocotyl explant of Charleston pepper in 3 mg L-1 BA+0.5 mg L-1 IAA, 80% from hypocotyl explant of capia pepper in 5 mg L-1 BA+0.5 mg L-1 and 84% from hypocotyl explant of bell pepper in 5 mg L-1 BA+0.5 mg L-1 IAA. Afterward, shoots were rooted and whole plants were obtained.