The seed yield of the primary inflorescence increased by the pinching off of the lateral buds on the first flowering day and 7 days after the first flowering due to the increase in the number of fruits. As the number of fruits per inflorescence hardly changed by the pinching off of the lateral buds conducted 14 days after the first flowering and later, it was suggested that the number of fruits should be determined before the 14th day after the first flowering. In those cases, the number of fruiting dichasia per inflorescence hardly changed, but the number of fruits per dichasium increased. This increase was caused by the fructification of the higher order flowers which bloomed later. The fourth order flowers at most in a dichasium bloomed and fructified in this study using the cultivar Shanghai. The fructification of the high order flowers usually gave rise to a mixture of immature and mature fruits at harvest and it is likely that the quality of oil became poor. It appears that the number of fruiting dichasia per inflorescence was determined at the inflorescence-developing-stage before flowering and that it slightly changed in this study because fruit setting took place in the mixed dichasia of male and female flowers. The seed weight seemed to be determined during the 30 day period after the first flowering. The length and the thickness of the seeds appeared to be determined 7 days later than the number of fruits which was earlier than in the case of the seed weight. The seed width appeared to be determined at the same time as the seed weight. Further investigations on the seed volume and seed weight should be carried out in future.

View full abstract

During the cropping season of 1988 to 1990, an experiment was conducted to analyse the individual as well as combined effects of certain managment practices on the growth and yield of sugarcane in Bangladesh. Eleven management practices for sugarcane cultivation were successively applied and compared with a control (Traditional farmer's practice) in a randomized complete block design with four replications using the sugarcane variety Ishurdi-16. The highest yield of cane (103.7 t/ha) and sugar (10.6 t/ha) were obtained by the combined use of all eleven management practices, while the lowest yield of cane (38.2 t/ha) and sugar (4.0 t/ha) were obtained in the control. The largest amount of recoverable sugar (11.6%) was obtained in the practice consisting of early planting (November), followed by the planting of canes in deep trenches (11.5%) . The effects of individual management practices resulted in an increase of the rate of cane yield over the control ranging from 1.5 to 70.1 percent. The largest increase of additional cane yield among the adopted management practices was 70.1 percent for the optimum amount of fertilizers applied, followed by irrigation which increased cane yields by 28.0 percent. The adoption of the combined eleven management practices resulted in the highest yield of cane, i. e. 171.5 percent over the control.

View full abstract

The current experiment was conducted to examine the effects of Fulmet liquid treatment on berry enlargement, development and quality in six European grape cultivars. The Fulmet liquid solution was applied to the berries of the rate of 5, 10 and 20 ppm 2 weeks after full bloom.
1. Effects of the Fulmet concentration on the weight of a berry and fruit cluster varied among the cultivars.
2. Although the berry enlargement of ‘Monuka’ and ‘Rizamat’ was enhanced the sugar acid ratio decreased. The berry growth of ‘Unicon’, ‘Mario’, ‘Nehelescol’ and ‘Baradi’ was stimulated, and the sugar acid ratio did not decrease appreciably.
3. Effects of Fulmet liquid treatment on the fruit quality were different among the European grape cultivars.

View full abstract

A study was carried out on the effect of the zinc concentrations in the nutrient solution and shade level on the growth, nitrogen content and nitrate reductase activity in tomato plants. The three zinc concentrations used were 0, 0.005 and 0.05 ppm. The four levels of shade used were 0%, 25%, 50% and 70%.
The height of the 0.05 ppm plants was the greatest compared to that of the other plants on Dec. 21 but only slightly greater than that of the 0.05 ppm plants on Dec. 7.
Total nitrogen content of the leaves showed no apparent differences in the 0, 0.005 and 0.05 ppm plants. On Dec. 21, the highest total nitrogen content was recorded in the 0.05 ppm plants. Total nitrogen content of the stems and roots showed the same tendency as that of the leaves.
The ratios of soluble nitrogen to total nitrogen in the Oppm plants was higher than in the 0.05 ppm plants.
Nitrate reductase activity of the leaves in the 0.05 ppm plants was the highest on both dates. Nitrate reductase activity of the stems was the highest in the 0.05 ppm plants on both dates. Nitrate reductase activity of the roots was lower than that of the leaves and stems on both dates.
In the shade experiment, the values for the fresh and dry weight of the plants not subjected to the shade treatment were the largest as compared to those of the other plants throughout the growth period.
Nitrate reductase activity of the leaves in the shade experiment was the highest in the plants not subjected to the shade treatment and lowest in the 70% shade plants on all the three dates. The nitrate reductase activity of the roots was the highest in the plants not subjected to the shade treatment on Apr. 12 and 19. But it was lower than that of the leaves and stems.

View full abstract

Different developmental stages of foxtail millet (Setaria italica L. BEAUV.) were studied during dry seasons in 1989 and 1990. Two cultivars, Bogra-1 and Titas, were employed in the study. Twelve morpholog-ically different and distict growth stages were identified, viz, seedling emergence, 3-leaf, 5-leaf, crown root initiation (CRI), maximum tillering (MT), panicle primordium initiation (PPI), flag leaf, booting, heading, milk, dough, and physiological maturity. Bogra-1 took 11 and 8 days more to attain physiological maturity than Titas in 1989 and 1990, respectively. In both years, growth rate was the highest at heading stage in Bogra-1 and at PPI stage in Titas, although leaf area in both cultivars was maximum on 41 days after emergence (DAE) of seedlings which was around PPI stage. Bogra-1 produced higher grain yield than Titas.

View full abstract

In order to develop the most efficient system of weed control, experiments in integrated weed control combining mechanical and chemical control with the use of leguminous covers, were carried out in a large plantation of Plau-Noi trees (1, 120 ha) .
Glyphosate, N- (Phosphonomethyl) glycine is one of the most important herbicides for weed control in Plau-Noi plantations. Although young Plau-Noi trees less than two years old can be damaged by the application of agricultural chemicals such as glyphosate, adult Plau-Noi trees more that 2 m high are not affected by such applications. Therefore, the following weed control program was designed and adopted.
Effective weed control in young Plau-Noi plantations consisted of integrated control including cutting, digging and plowing using farm implements, and weeding by utilizing the competitive growth between herbaceous weeds and cover crops. On the other hand, in adult Plau-Noi plantations chemical control consisting of the application of glyphosate at rates ranging from 1.4 to 3.3 kg a.i./ha. was adopted.

View full abstract

Three different types of proliferative responses were induced, when transversely-sliced tissues of coconut embryo were cultured in the medium supplemented with 100 ppm of 2, 4-dichlorophenoxyacetic acid (2, 4-D) and 0.25% of activated carbon. On the basis of morphological features induced, these proliferations were categorized as Types I, II and III; Type I: whitish nodular callus, Type II: yellowish rounded callus, and Type III: whitish dome-like mass by explant enlargement. The initiation of Type I took place from tissues of the proximal portion, while Types II and III were induced specifically from the middle and distal portions. For surveying the fate of individual proliferation, further structural changes were monitored closely during subculturing over several times. No sign of organogenesis was observed in Type I which retained as the state of callus, although its growing surface changed into a coarse granular appearance. In contrast, the Types II and III gave rise to roots and haustorium-like structures, respectively.

View full abstract

A simple testing method for salt tolerance was developed in order to improve the efficiency of selection in breeding procedures, as follows.
Young seedlings are transplanted to petri dishes filled with sand and moistened with salt solutions at four concentration levels. About 10 days later, the height of the cultured seedlings is measured and linear regression equations of plant height of the crops tested on the salt concentration index are derived. The linear regression coefficients of each crop are standardized in order to eliminate the difference in plant size under normal conditions. A smaller coefficient (absolute value) indicates a higher salt tolerance.
This testing method is recommended due to the small number of seeds required, the short duration of the test and the relatively high accuracy of the results. It is especially useful for breeding work for salt tolerance in which a certain number of materials has to be checked in a short period of time in order to select tolerant lines.

View full abstract

Growth, yield and physiological characteristics in hexaploid triticale (×Triticosecale WITTMACK) were analyzed under salt and water stress conditions. Two cultivars, Welsh (substitution type) and Currency (complete type), were employed in this study. Growth and yield were remarkably reduced by the combined effect of salt and water stress than by either of the two kinds of stress. Continuation of saline irrigation with 100 mM NaCl solution in Currency and 50 mM NaCl solution in Welsh reduced the yield-loss caused by water stress. Photosynthetic rate was decreased by salinity in Welsh but was not affected in Currency. However, the values of this parameter were decreased by water stress and by combined salt and water stress in both cultivars. No consistent relationship was observed between photosynthetic rate and any of stomatal resistance, intercellular CO₂ concentration, transpiration rate, and leaf water potential under salt stress conditions. However, some relationships were observed between the above parameters under water stress, and combined salt and water stress conditions. Transpiration rate and leaf water potential were decreased under both kinds of stress conditions. Chloride, sodium and potassium concentrations in the leaves were pronouncedly increased when water stress was imposed on salt affected plants. Accumulating tendency to calcium and magnesium in the leaves was not similar in the two cultivars but that to potassium was similar, which may suggest that potassium rather than calcium and magnesium plays an important role in osmoregulation in triticale plants under stress conditions.

View full abstract