Provenance variation of ziziphus spina-christi (L.) desf, in seed and seedling characteristics

The objective of this work was to study Ziziphus spina-christi (L.) Desf, at the provenance level to evaluate its variation in seed and seedling characteristics among four selected provenances; Damazin, Sinar, Khartoum and Elfashir, Fruits and soil samples were collected from these provenances, seeds and seedling experiments were conducted at the National Seed Centre laboratory, and the nursery of Forestry Research Centre at Soba, in the season June - October/ 2007. The work examined the fruit size and color visually, and the experiments were performed on; fruit pulp weight, seed status, seed purity, seed moisture content, seed viability, seed germination, seed chemical contents and seed dormancy. In the nursery experiment, every seed source was sawn on its own soil sample and the soil samples of the other three provenances. After a period of seedling establishment, three irrigation regimes; once a week, twice a week and once every two weeks were applied. Variation in fruit size and color was observed visually and the source of Damazin provenance showed the biggest fruit size followed by Elfashir, Khartoum and Sinar provenances. Damazin fruit source was darker brown, Khartoum and Sinar fruit sources were lighter and Elfashir fruit source was in-between of dark brown and light brown. The study showed very high significant differences between the four sources in pulp weight (P = 0.0001), and Damazin provenance was the highest mean weight. Damazin and Sinar seed sources showed the highest percentage of sound seeds; (100%). The study showed no significant differences between the four sources in seed purity, Sinar and Damazin provenances were (100%) pure seeds followed by Elfashir provenance; (99.8 %) and Khartoum provenance; (99.7 %). There were highly significant differences in number of fruits/kg (P = 0.001), and number ofseedslkg (P = 0.001), where Sinar source showed the highest mean of number of fruits/kg, and Damazin source showed the highest mean of number of seeds/kg. Seed moisture content and seed viability showed no differences between the four provenances. The biochemical experiment results revealed variation in some biochemical contents among these provenances, seed oil and protein of Damazin provenance showed the highest percentages. Khartoum source was the highest seed phosphorus. Elfashir provenance seeds had the highest percentage of carbohydrates, and the highest potassium content. The study observed a very high significant germination response of big seeds of the four sources to the dormancy breaking treatments (P = 0.0001), and seed extraction, sulphuric acid for one hour and for thirty minutes, and boiled water were the best treatments. Also, the effect of provenance on big seed germination was highly significant (P = 0.001) and Damazin provenance showed the highest mean of germination percentages. Germination of small seeds of the four provenance sources gave a very high significant response to the dormancy breaking treatments (P = 0.0001), and seed extraction, sulphuric acid for one hour and for thirty minutes, and boiled water were the best treatments. There was no significant provenance effect on small seed germination. The germination of twins from big seeds gave a very high significant response to the dormancy breaking treatments (P = 0.0001), and provenance effect on emergence of big seed twins was highly significant (P = 0.002), where Damazin provenance showed the highest mean of twin percentage. The study showed significant seedling growth responses to the irrigation regime once a week for; shoot fresh weight (P = 0.014), root fresh weight (P = 0.017), shoot dry weight (0.024) and root dry weight (P = 0.004). The irrigation regime twice a week was effective on number of leaves (P = 0.015), root length (P = 0.039), shoot fresh weight (P = 0.038), root fresh weight (P = 0.016), shoot dry weight (P = 0.042) and root dry weight (P = 0.036). On the other hand, very high significant responses to the three irrigation regimes were observed on the seedling characteristics and twice a week gave the highest parameter means. The study revealed no differences in seedling characteristics when the irrigation regime once every two weeks was applied and no significant seedling growth response to the soil types and provenance when any of the three irrigation regimes was applied. The differences between the effects of the three irrigation regimes on seedling characteristics showed very high significant number of leaves (P = 0.0001), and once a week gave the highest mean (39.22). The response of shoot length was also very high significant (P = 0.0001), and twice a week showed the highest mean of shoot length (32.86 cm). The response of root length to the three irrigation regimes was significant (P = 0.024), where twice a week and once a week gave the highest means (18.29 cm) and (17.90 cm). In addition, shoot fresh weight gave the highest response (P = 0.0001), twice a week and once a week gave the highest means (4.19 g) and (3.19g). The study revealed very high significant responses of; root fresh weight (P = 0.0004), shoot dry weight (P = 0.0001) and root dry weight (P = 0.0009) to these three irrigation regimes, and twice a week gave the highest means of these characteristics (2.91 g), (2.68 g) and (1.79 g). The study recommended the use of sulphuric acid as the most suitable treatment to release seed dormancy of Ziziphus spina-christi