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Volume 43, Issue 4
Displaying 1-12 of 12 articles from this issue
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Suranant SUBHADRABANDHU, Kusol IAMSUB, Ikuo KATAOKA1999 Volume 43 Issue 4 Pages 249-253
Published: December 01, 1999
Released on J-STAGE: March 19, 2010
JOURNAL FREE ACCESSThe study was conducted to analyze the effect of paclobutrazol application by several methods on the vegetative and reproductive growth of mango trees, and to detect its residues in the leaves and soil. Paclobutrazol was applied to‘Nam Dok Mai’as (1) foliar spray at 1, 000 ppm, (2) foliar spray at 1, 000 ppm and covering of soil underneath the canopy with a plastic sheet allow the chemical to penetrate only through the leaves, (3) soil drenching at a level of 8 grams/tree and (4) trunk injection at a level of 400 mg/tree. Soil drenching was most effective in suppressing shoot elongation. Flowering ratio in the trees subjected to all the paclobutrazol treatments was higher than that of the control, but the fruit set only slightly increased by these treatments. Paclobutrazol remained in the soil up to 11 months when it was applied to soil and three months in foliar spray without soil cover. No residues were detected in the soil when paclobutrazol was applied by foliar spray and covering of the soil as well as trunk injection. The level of the residues was high in the leaves subjected to foliar spray, while it was considerably low in the case of soil application and trunk injection. In all the treatments, no chemical residues were detected in the mature fruits.View full abstractDownload PDF (656K) -
Chuangen LU, Jiangshi ZOU, Hiroshi IKEHASHI1999 Volume 43 Issue 4 Pages 254-259
Published: December 01, 1999
Released on J-STAGE: March 19, 2010
JOURNAL FREE ACCESSThe present study was carried out to examine the effect of low temperature on the spikelet fertility of indica-japonica hybrids, and to investigate the factors responsible for male gamete abortion. The spikelet fertility of F1 hybrids of five crosses was significantly reduced at low temperatures just before flowering. The reduced spikelet fertility was considered to be related to pollen fertility which was expressed by the ratio of stained pollen grains and distorted segregation of markers in the progenies. At a lower temperature, the fertility of pollen expressed by the ratio of stained pollen grains was reduced, indicating that some of the male gametes were weakened or had lost their function in fertilization. Utilization of distortion-neutral genes to stabilize pollen fertility was proposed.View full abstractDownload PDF (683K) -
Yoshimi YONEMOTO, Hirokazu HIGUCHI, Tetsu NAKANISHI, Eiichi TOMITA1999 Volume 43 Issue 4 Pages 260-264
Published: December 01, 1999
Released on J-STAGE: March 19, 2010
JOURNAL FREE ACCESSMicroscopic observations of cherimoya (Annona cherimola Mill.) pollen before shedding and during germination found that tetrad pollen was formed in vertical furrows of the anther. The diameter of the swollen pollen grains was approximately 50 μm. In vitro conditions for pollen germination and tube elongation of freshly collected cherimoya cultivars, ‘Sabor’, ‘Pierce’, ‘El Bumpo’, ‘Villapark’ grown under plastic house conditions were studied. Pollen germination and tube elongation were prominent on 2% agar media containing 15-20% sucrose. The optimum temperature for pollen germination and tube elongation was 22-25°C. Addition of 10-500ppm boric acid to 2% agar medium containing 15% sucrose accelerated the pollen germination and tube elongation.View full abstractDownload PDF (2408K) -
Nobuo OKAGAMI, Keisuke TERUI, Hajime ARAKI, Toshinari KANAZAWA, Masash ...1999 Volume 43 Issue 4 Pages 265-270
Published: December 01, 1999
Released on J-STAGE: March 19, 2010
JOURNAL FREE ACCESSThe species in the genus Dioscorea, a group of monocotyledonous perennials, grow mainly at the margin of forests in the humid tropics and some members are cultivated around their native growing zones as yams. To obtain information on the germination behavior of African Dioscorea, the conditions for seed germination of six species collected in Nigeria were tested at temperatures ranging from 10 to 35°C. The species studied were Dioscorea abyssinica, D. bulbifera, D. dumetorum, D. preusii, D. schimperiana, D. togoensis. Seeds of all the species displayed rapid germination at temperatures around 26°C and also exhibited high-temperature inhibition of the germination. The lowest temperature for germination was 20°C in all the species. The highest temperature at which germination occurred differed among the species. Almost all the ungerminated seeds incubated at 32 and 35°C germinated rapidly after transfer to 26°C. This rapid recovery of germination, also observed in the temperate European and tropical Asian species of Dioscoreaceae, indicates that high temperatures such as 32 or 35°C do not induce the secondary dormancy which has been observed in temperate Asian species.
Naked embryos isolated from the African Dioscorea seeds germinated rapidly even at higher temperatures than those at which intact seeds germinate. The germination behavior of the intact seeds is considered to be controlled by other seed parts than embryo. After the germination, a callus was formed on a part of the naked embryo when it was incubated at temperatures above 29°C.
Information on the seed germination of tested species may contribute to the improvement of cultivation and breeding of these species.View full abstractDownload PDF (2599K) -
Takayoshi TERAUCHI, Makoto MATSUOKA, Makoto KOBAYASHI, Hiroshi NAKANO1999 Volume 43 Issue 4 Pages 271-276
Published: December 01, 1999
Released on J-STAGE: March 19, 2010
JOURNAL FREE ACCESSChanges in stalk elongation and Brix value of early maturing sugarcane varieties with a high sugar content were compared to those in conventional varieties in a field of 12-month crop. Acid invertase (AI) and neutral invertase (NI) activities were also measured to analyze the physiological characteristics of the early maturing sugar cane variety with a high sugar content.
Typical Brix value increment patterns of each variety were observed. The Brix value of NiF4, a typical early maturing variety with a high sugar content, increased in August while the stalk elongation rate of this variety decreased. The ratio of carbohydrate distribution to sucrose accumulation increased in August in this variety.
AI activity, a negative factor for sucrose accumulation, decreased in NiF4 in August. The decline of AI activity may contribute to the increase of the sucrose concentration of this variety through the inhibition of stalk elongation. AI activity was relatively higher in NiF4 than in F172. It is unlikely that the level of AI activity caused varietal differences in sucrose concentration. NI activity, a positive factor for sucrose accumulation, was higher in NiF4 than in F172 throughout the seasons. It is possible that NI activity contributed to sucrose accumulation through the high flux of sugars in NiF4. These observations suggest that the re-combination pathway of sucrose accumulation should be investigated.View full abstractDownload PDF (794K) -
An Approach Using Frontier Cost FunctionAlbert P. AQUINO, Atsushi MARUYAMA, Masao KIKUCHI1999 Volume 43 Issue 4 Pages 277-284
Published: December 01, 1999
Released on J-STAGE: March 19, 2010
JOURNAL FREE ACCESSUsing the data obtained from corn farmers in the major corn producing province of Cagayan Valley in the Philippines, a stochastic frontier cost function was estimated. We found that the average cost function was located 20% above the frontier function, reflecting the existence of significant technical inefficiency among the corn farmers. Considering the present level of price difference between the domestic and international corn markets, however, the total reduction of this degree of technical inefficiency, even if possible, is not sufficient to make corn farming in the Philippines competitive enough. If the competitiveness of Philippine corn production were to be maintained or strengthened, larger efforts in research for continuous enhancement of the technology frontier itself at a rapid pace should be made.View full abstractDownload PDF (974K) -
Daigo MAKIHARA, Makoto TSUDA, Miho MORITA, Yoshihiko HIRAI, Toshiro KU ...1999 Volume 43 Issue 4 Pages 285-294
Published: December 01, 1999
Released on J-STAGE: March 19, 2010
JOURNAL FREE ACCESSGrowth and yield responses of rice (Oryza sativa L.) to soil salinity were studied in six varieties differing in tolerance at the seedling stage. Plants were grown in four-liter pots containing soil treated with sodium chloride at a rate of 5g/pot, 10g/pot and 15g/pot, and control plants were grown without application of sodium chloride. Varieties tolerant at the seedling stage (Kala Rata 1-24 and IR4595-4-1-13) grew well under salinity, but in other tolerant varieties (Nona Bokra and Pokkali) leaf emergence, tillering and plant length were suppressed by salinity at a similar degree as in the sensitive varieties (IR28 and Mangasa) . The decrease in yield was more conspicuous in IR28, Mangasa and Pokkali than in the other three varieties. Yield components responsible for the yield reduction varied: small number of spikelets in IR28 and Pokkali, and high sterility induced by white heads in Mangasa. Sodium concentration of panicle peduncle and flag and the uppermost third leaves at the maturing stage was similar in all the varieties except for Mangasa which showed the lowest sodium concentration. These results supported the assumption that salinity-tolerant varieties at the seedling stage do not always maintain grain yield at a sufficient level under salinity, and indicated that the plant ability to maintain a low level of sodium concentration is not related to salinity tolerance throughout the growth period.View full abstractDownload PDF (1081K) -
Chuangen LU, Jiangshi ZOU, Hiroshi IKEHASHI1999 Volume 43 Issue 4 Pages 295-299
Published: December 01, 1999
Released on J-STAGE: March 19, 2010
JOURNAL FREE ACCESSThe purpose of this study was to determine whether gamete abortion in wide crosses can be related to spikelet or pollen fertility using marker genotypes. In a cross among the plants possessing the homozygous genotype of Pgi-122 on Chromosome 3, the heterozygous genotype Est-912 on Chromosome 7 segregated a large number of plants with pollen sterility compared with the plants with the homozygous genotype Est-911. Pollen fertility of the plants possessing heterozygous genotypes both at the Pgi-1 and Est-9 loci was much lower than that of plants with the homozygous genotype Pgi-122/Est-911. In another cross using two marker genes Pgi-1 and A (Anthocyanin activator, on Chromosome 1) the plants with the heterozygous genotype Pgi-112 or A/A+ which were derived from two distant parents were found to segregate more pollen-sterile plants than those with the homozygous genotype Pgi-122 or A+/A+. Thus, Pgi-1 and A were found to be related to the fertility of pollen without any direct relation with spikelet fertility. The results implied that ga-14 (t) and ga-7 which are linked to Pgi-1 and A, respectively, may have affected the pollen fertility. The reduced pollen fertility was found to decrease the spikelet fertility in the tested crosses. In addition, spikelet fertility in the hybrids was confirmed to be related to C (Chromogen for pigmentation) on Chromosome 6. These findings should be useful for breeding such lines that show normal gamete fertility in wide crosses.View full abstractDownload PDF (644K) -
Ike EZENWA, Ayuba Francis JACOB1999 Volume 43 Issue 4 Pages 300-305
Published: December 01, 1999
Released on J-STAGE: March 19, 2010
JOURNAL FREE ACCESSA study was conducted at Ibadan (7°20'N, 3°50'E; 200 m above sea level), southwest Nigeria, to determine the feasibility of growing arable crops during the establishment of Enterolobium-guinea grass mixture. Following the planting of Enterolobium at the beginning of the planting season (May 1997), the crops were planted as companions in the 4 m-wide alleys of the tree in the following cropping sequences in the first/second seasons: (1) No cropping/guinea grass-sasage (cowpea, Vigna unguiculata (L.) Walp.) (Treatment 1), (2) Maize/guinea grass-sasage (Treatment 2), (3) Maize-guinea grass/guinea grass (Treatment 3), and (4) No cropping in both seasons (Treatment 4) . Treatments 1 and 2 gave the highest total biomass (maize stover and/or sasage residue, excluding grains) of 5.35 and 5.68 t DM/ha and Treatment 2 gave the highest total grain (maize and sasage) yield of 1.60 t/ha. In Treatments 2 and 3, the companion crops adversely affected tree growth significantly in the second season. At 36 weeks after planting, the tree height was 98.6, 94.6, 62.6 and 36.0 cm in Treatments 1, 4, 2 and 3, respectively. Enterolobium-guinea grass mixture can be profitably established either by planting the tree alone in the first season and introducing guinea grass and sasage in the second season (Treatment 1) or by planting the tree with maize in the first season and sasage and guinea grass in the second season (Treatment 2) . The first cropping system optimizes tree growth while the second optimizes total grain yield.View full abstractDownload PDF (810K) -
Keiko YOSHINO, Kazuo ANDO1999 Volume 43 Issue 4 Pages 306-318
Published: December 01, 1999
Released on J-STAGE: March 19, 2010
JOURNAL FREE ACCESSStudy on homestead (bari-bhiti) utilization and management was carried out in the Dakshin Chamuria village located in the floodplain of the tributary of the Jamuna river in Bangladesh from 1992 to 1995. Interviews of 12 sample households, detailed plantation mapping survey in sample compound in which 17 households lived, and interviews on the use and management of various plants were conducted. In the whole village, 125 species (82 species of perennial plants and 43 species of annually grown plants) were observed and each plant had various uses. Seventy species were used as food materials, about 80 species were used for fuel, 48 species were used as medicine, 8 species as fodder, 8 species as livestock medicine, 24 species as timber, 17 species as material for various tools, 3 species were used for soil protection, and other uses such as hedge, child's play, ornamentals, etc. for the villagers' daily needs. One plant was used for 2.5 purposes on the average among all the plants, and 2.8 among the perennial plants. Multiple use was conspicuous for the indigenous and common species to the locality, indicating the presence of a close relationship with the living environment of the villagers. Being located on the floodplain, homestead in the D village needs to be elevated, which is labor-and cost intensive, to avoid the inundation in the rainy season. Under such hydrological limitations, the villagers have developed a holistic plant utilization system, which places emphasis on the sustainability and totality, and is filled with wisdom and indigenous knowledge in terms of lifestyle.View full abstractDownload PDF (1630K) -
1999 Volume 43 Issue 4 Pages 321a-323
Published: 1999
Released on J-STAGE: March 19, 2010
JOURNAL FREE ACCESSDownload PDF (385K) -
1999 Volume 43 Issue 4 Pages 321b-323
Published: 1999
Released on J-STAGE: March 19, 2010
JOURNAL FREE ACCESSDownload PDF (385K)
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