Wild Mangifera species were explored in northeast Thailand, central and northern Laos and northwest Vietnam, in which Tai language families settle. Their morphological characteristics, local names and uses were recorded, and their growing environments were compared. We observed 260 wild Mangifera trees, and we classified them into four groups based on morphological characteristics of leaves and tree shape. Broad-leaf type was distributed in flatland of Thailand and Laos and called muang paa or muang khan, respectively. Slender-leaf type was distributed in mountainous areas of Vietnam and Laos, and was called muang khai in central Laos, muang kaeo noi in northern Laos and moi or mak chai in Vietnam. Long-leaf type grew only in the Laotian forests, and names were not consistent. Type with leaves similar to those of cultivated mango was found constantly, and was called by several names in each area. Muang kalon have been explained as M. caloneura, while some of the trees were possibly considered to be M. indica, indicating that the recognition of “wild edible mango” could have drifted from M. caloneura to the old local varieties of M. indica. The leaves of muang kasoo in Laos were used as food and its bark as dye and medicine, while most wild Mangifera were mainly used for fruits and woods. In the flatland of Thailand and Laos, trees often grew in croplands. They were assumed to have been conserved from the original forest. In the mountainous areas of Laos, the villagers used wild Mangifera trees in the forest, while they had no intention to conserve useful trees. In northwest Vietnam, wild Mangifera trees were transplanted into the villages before the forest had been reclaimed for crop fields, possibly implying a first step in the domestication of wild fruit trees.
The present study evaluated the effect of various ranges of controlled air temperatures (day-night air temperature; 23-15°C, 27-19°C, 31-23°C, and 35-27°C) on the growth and nutrient status of sago palm seedlings. Seedlings grown at the air temperature of 31-23°C displayed the highest plant length increment, while at the highest air temperature (35-27°C), the seedlings showed the lowest plant length increment. Delay in new leaf emergence was more pronounced at the lower air temperatures (23-15°C and 27-19°C) than at the higher ones (31-23°C and 35-27°C) and the production of new leaves declined when the air temperature decreased. The highest and lowest temperatures reduced the SPAD values almost simultaneously but the reduction was more pronounced at the highest temperature. The maximum leaf area was observed at the air temperature of 31-23°C, followed by 35-27°C. The seedlings showed a higher value of shoot dry weight as the air temperature increased, up to 31-23°C when the maximum value of the shoot dry weight was recorded. The highest (35-27°C) and the lowest (23-15°C) air temperatures inhibited root growth, though the number of adventitious roots was not affected. The maximum value of the root dry weight was recorded at the air temperature of 27-19°C. Growth at the air temperature of 31-23°C led to the highest uptake of N, P, K, and Ca, while the uptake of Mg was the highest at 27-19°C. The optimum air temperature range required for adequate growth is probably within 31 to 23°C. In this air temperature range, the maximum number of leaflets, leaf area, and uptake of N, P, K, and Ca could be obtained.
The effects of NaCl concentrations (0, 50, 100, 200 and 400 mM) on the growth parameters, dry matter production, water content, stomata number, mineral content and proline content of torpedograss (Panicum repens L.) were evaluated to elucidate the salt tolerance mechanism of the plant. The values of all the growth parameters of torpedograss decreased with increasing concentrations of NaCl. Water content in the plants decreased from 84.5 to 68.0% under a salt stress of 400 mM. The contents of Na+, K+ and Ca2+ in the plants increased with increasing salt concentrations at 28 days after treatment (DAT). Shoot dry matter production was negatively correlated with the increase of Na+ content in shoots at 14 (r = -0.95) and 28 DAT (r = -0.93). Proline content increased by 10 and 100 fold under the salt stress of 200 and 400 mM, respectively, compared to that in the control plants. Positive correlation was observed between the proline content and Na+ content in shoots at 14 (r = 0.82) and 28 DAT (r = 0.94). Although torpedograss survived under a 200 mM NaCl stress, the plants grown under a 400 mM NaCl stress accumulated a high level of Na+ in cells at the early stage, which was severely toxic and led to the plant death at 21 DAT. The present study indicated that torpedograss maintained an adequate water content (about 68%), and accumulated higher levels of K+, Ca2+ and proline for maintaining the ion balance and osmoregulatory activities in cells to survive under NaCl stress conditions.
Indonesia is the 3rd largest cocoa-producing country in the world. The cacao varieties currently cultivated in Indonesia are inter-hybrids of various clones introduced from the Americas since the 16th century. Among them, “Java cocoa” is a well-known fine cocoa specialty product which was originally selected from crosses between “Java Criollo” trees and an unknown parent at Djati Roenggo, Java in 1912. Using simple sequence repeat (SSR) markers, we analyzed the genetic diversity and population structure of fine-flavored cacao germplasm from Java, and compared the results with those of bulk cocoa in the same region. Although a high level of heterozygosity was observed in the fine-flavored cacao clones (Ho=0.660; He=0.674), indicating their hybrid origin, the allele richness in the Java cacao germplasm was moderate (7.6 alleles per locus). Principal Coordinate Analysis (PCoA) showed that the genetic structure of Java cocoa is heterogeneous, including genetic background of Trinitario, Upper Amazon and Lower Amazon Forastero. Parentage analysis supported the passport records of parental contribution from Venezuelan landraces to some DR clones (DR 1 and DR 38), which are the main clones used to produce Java cocoa, but excluded the direct parentage of pure Criollo. Sibship reconstruction indicated that the DR clones did not originate from a single cross as previously considered. The resultant information improved our analysis of the diversity and ancestry of Java cocoa. It also suggested the need for broadening the genetic background in the Java cocoa germplasm.
Seeds of three okra (Abelmoschus esculentus) cultivars were sown in plastic containers with artificial soil mix, and their emergence was examined at 17.5°C, 20°C, 25°C, 30°C, 35°C and 40°C to determine the optimum emergence temperature of the seeds. Emergence started earlier in the 30°C, 35°C and 40°C groups than in the other groups for all three cultivars at two days after sowing, and the emergence percentages on the day of emergence were higher for the 35°C group in two cultivars than for the other groups and for the 35°C and 40°C groups in one cultivar. On the day following emergence, a higher percentage of emergence for all three cultivars was obtained at 35°C than at 40°C. At 30°C and below, the emergence of all three cultivars was delayed as the temperature decreased. The average number of days to emergence was shorter in the 35°C group than in the other groups for one cultivar and in the 35°C and 40°C groups for two cultivars. The final emergence percentages during the study period were 94.7-99.7% in the 20°C, 25°C, 30°C and 35 °C groups in two cultivars and 86.3-91.7% in the 25°C, 30°C and 35°C groups for one cultivar. Based on these results, the optimum emergence temperature for the okra seeds of the three cultivars was 35°C within the limits of the experiment.