Mangifera pentandra trees are common in Northeast Thailand, where they are known locally as kalon mango or paa mango. Kalon mango is recognized as being better-tasting than paa mango, but both belong to the same species. The differences between kalon and paa mangoes have not been previously examined. We recorded and interpreted indigenous knowledge of M. pentandra in Northeast Thailand, thereby contributing relevant information to future generations of local people. We also considered people–plant relationships in the process of fruit tree domestication. Our survey included 171 trees of M. pentandra found growing in crop fields, along roadsides, and in close vicinity to human habitats. All of these sites had been transformed from an original vegetation of mixed dipterocarp forest. One-third of the M. pentandra trees in our survey were recognized locally as kalon mango, while most of the remaining trees were paa mango. Kalon mango fruits were bigger than those of paa mango and had a higher sugar content. A dense, dome-shaped canopy, thin, narrow leaves, and pale-brown bark distinguished kalon mango trees from paa mango. Many paa mango trees found growing in crop fields were very large; the smaller kalon mango trees tended to occur near human settlement. We therefore propose that paa mango trees are remnants of natural forest and that kalon mango trees have been planted recently. Kalon mango may be the product of subconscious selection for superior fruits that are larger and better-tasting than the wild type.
Swidden agriculture, which is still widespread in the mountainous areas of northern Laos, is evolving rapidly due to the economic, political, and social changes related to the practice. In this study, as part of efforts to clarify important changes and causal factors related to future agricultural development in this region, field surveys were conducted to ascertain the current conditions of the cultivation, labor input, and previous conditions related to swidden agriculture in a village of northern Laos. In the study area, upland rice was the main crop, and its swidden fields were found to average 1.22 ha in size and had fallow periods averaging 8.8 years. It was found that fallow periods varied widely from two to 20 years, and were longer in remote areas than in locations close to the settlement, but no significant differences were noted in the upland rice yields of swidden fields with different fallow periods. Among swidden farm practices, weeding required the largest labor input, and accounted for 67 man-days per ha, or 46% of all labor input. Furthermore, labor shortages were observed in some households because family members engaged in other work to generate cash income. This caused delay of weeding and weed infestation, which resulted in abandonment of the swidden field in some cases. Based on the result of interviews with elder villagers, the swidden agriculture practices in the area from 1980s to 1990s can be summarized as follows: in a normal year, field sizes averaged 3.2 ha, fallow periods tended to be longer than nine years, or averaged between 10 to 15 years, and full-field weeding was practiced two to three times per crop cycle. While this weeding requirement is similar to the present time, less labor was required because there were less herbaceous weeds. In the study area, there have been three primary changes to swidden agriculture: field area reduction, gradual fallow period shortening, and increasing burdens of the swidden works. The main causal factors were the government’s resettlement program, population concentration in roadside areas, increased labor requirements resulting from increased weed, and increased distance of swidden field from residences. These changes and their causes were interrelated and synergistic. Especially, increased weed and weed management programs are closely related to them, and the transformation of swidden agriculture could proceed more conspicuously and rapidly by the future introduction of herbicides or other new technologies that can be expected to alleviate weed problems.
The present study aimed to prevent tree-ripened ‘Irwin’ mangos from being damaged when transported over long distances. We examined the effects of differences in the peak acceleration (PAcc) of the external shock, as well as the number of repeated shocks, on damage to mangos. The results suggested that damage to ripened mangos was caused by cumulative fatigue, and the degree of damage (D) when a given level of PAcc had been applied to mangos was calculated. We also analysed the shock conditions during mango transportation, including by ship, and predicted the damage during transportation based on the above relationship between PAcc and D. Although damage to mangos was not predicted for the transportation routes that had been selected for examination in the present study, the results also suggested that the cushioning ability of the existing packaging may be insufficient depending on the condition of the mangos. In the present study, therefore, laboratory tests were conducted to examine the relationships between PAcc, the number of repeated shocks, and damage to the fruit; an analysis was conducted to measure the shock during transportation. These results may enable to develop measures to prevent damage to tree-ripened mangos depending on the route and method of transportation.
A total of 95 households from five mountainous villages in Hong Ha Commune, A Luoi District, Thua Thien Hue Province, Vietnam were surveyed to investigate the function and significance of home garden practices in their livelihood. The results showed that the average home garden size was about 1000m2 with 30% of the households having fish ponds. Using this land resource, households were enjoyed in various cultivation activities. The main source of income from home gardens was derived from products from annual and perennial crops, which were primarily used for daily consumption and occasionally for cash income. The dominant seasonal crops, such as taro, Sauropus androgynus L., papaya, Piper lolot, lemongrass and sweet potato, were grown and harvested all year round while other crops were harvested in the rainy season. Perennial crops were normally harvested during the dry season whenfew annual crops were harvested. In addition, perennial crops also function well as wind breaks, provide shade for the garden, supply organic matter to the soil and act as host trees for plant vines to cling to. The contribution of home gardens to income was more significant for poor households. Thus, home gardens not only ensured food security for families but also contributed cash income to improve the livelihood of households in this area.
Rice is the second largest source of food energy in sub-Saharan Africa and its consumption has been increasing most rapidly among major food grains. A large part of this increase has been satisfied by import, absorbing as much as one-third of the rice traded in the world. The need to enhance food-security makes it imperative for countries in the region to reduce the dependence on the import. It has been said that a barrier to attaining this target is urban consumers’ preference of imported rice over domestic rice that is of lower quality. Although there has been a great proliferation of the literature on rice in sub-Saharan Africa, no attempt has been made to present an overall perspective of the national rice retail market that shows the structure of rice consumption in terms of quantity and quality by area of consumption and country of origin. Using data obtained from nation-wide market surveys, this paper describes the structure of the rice retail market in Uganda. The market comprises a traditional segment formed by public markets throughout the country with 95% of consumption and a modern segment formed by supermarkets all over the country with remaining 5%. Both segments are efficient and linked to each other. Contrary to the pessimistic view pervasive in the literature, local rice in Uganda is popular in the market and imported rice is priced to be competitive with the local rice brand preferred by consumers.
Off-types or alien plants are frequently found in the certified seed (R) fields of seed production farmers in Madagascar. The contamination is also observed to a lesser extent in the fields for breeder’s seed (G0) and foundation seed (G1) which are under the management of official agencies of seed production. Contamination discourages considerably the motivation of seed production farmers due to the need to remove off-types and to the decrease of the working efficiency at harvest. To maintain a high purity of G0 in Madagascar, the line cultivation method which is utilized for the maintenance of G1 in Japan was introduced. Thirty plants which represent the probable characteristics of the variety were uprooted in G0 fields at harvest time. With the analysis of morphological traits such as plant height, number of panicles and seed characteristics, the number of plants was reduced to twenty, which were treated as pedigree lines for the line cultivation in the following season for the selection of the next G0. Effects of the selection through line cultivation were evaluated including the variation of morphological traits, heading duration and percentage of off-types. Coefficient of variation (CV) of some of the morphological traits apparently decreased, heading duration based on the days from the beginning to the end of the panicle appearance was considerably shortened, and the percentage of off-types was reduced to 0.8% from 12.0%. These results indicate the effectiveness of the adoption of the line cultivation method for the purification of G0.
The present study investigated a new cropping system for cultivation of off-season yam after lowland rice. The experiments were carried out at IITA in Ibadan, Nigeria. The institute is located in a derived savanna, with the rainy season occurring from April to November and the dry season from December to March. Rice and white yam crops were rotated. The dormancy period of seed tubers was shifted using vine propagation. The first crop in this experiment was rice (September 2009 to January 2010), followed by yam (February to September 2010), and then rice again (September 2010 to January 2011). Four treatments were applied: a control of rice–yam–rice rotation without nitrogen (N) application at any phase; rice without N, followed by yam with 60 kg ha-1 N followed by rice without N; rice with 30 kg ha-1 N followed by yam without N, followed by rice without N; and rice with 30 kg ha-1 N, followed by yam with 60 kg ha-1 N, followed by rice without N. Nitrogen application to the yam cropping increased tuber yield. The comparable yields between the first and second rice croppings in the control treatment indicated that the intervening yam cropping did not reduce the yield of rice. The yam cropping did not leave behind additional effective nutrients that would affect rice cropping. These results suggested that lowland rice–yam crop rotation is a suitable new system for sustainable land use for yam.