 หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Relationship between Subtending Leaf Irradiance and Fruit Production and Quality of Cotton (Gossypium hirsutum L.)) ผู้เขียน: ดร.ศรปราชญ์ ธไนศวรรยางกูร, รองศาสตราจารย์ ,  Herve Sinoquet, Pascal Clouvel, Michel Cretenet, Eric Jallas สื่อสิ่งพิมพ์:pdf AbstractSubtending leaf has been known to be a major source of photosynthate for the attached boll, but little is known about quantitative relationship between actual variability of subtending leaf irradiance and boll production and fiber quality. The objective of this study was to quantify this relationship by using low-cost photoelectric sensor mounted on subtending leaf surface for leaf irradiance measurement during 4 different periods of boll development, i.e. from squaring to 5 days after anthesis (DAA), from anthesis to 25 DAA (fiber elongation period), from 15 to 45 DAA (fiber thickening period), and from squaring to 45 DAA (Whole reproductive period), and the Advanced Fiber Information System (AFIS) for fiber quality analysis. There were large variabilities of boll and boll component production, but less for fiber quality parameters, except short fiber content (SFC). Photosynthetically active radiation (PAR) captured by subtending leaves showed a substantial variation for each period of boll development whereas cumulative degree day (DD) was less variable. Variability of light captured by subtending leaf (LCS) was positively correlated with subtending leaf size. Increase in LCS during squaring -5 DAA resulted significantly in increased number of seeds and fibers per boll. During reproductive period (i.e. from squaring to 45 DAA). Increasing LCS could increase significantly dry matter of the boll, seed cotton, carpel, delinted seed, and fiber. However, variability of LCS during fiber elongation period did not affect significantly fiber length (both mean length, L, and SFC). Fiber linear mass (FIN), were not significantly affected by variability of LCS during 15-45 DAA. In this study the DD during determining periods of boll-component development did not show significant influence on boll production and fiber quality. By hypothesizing that assimilates photosynthesized and stored in plant parts before the determining periods might also be used for fiber growth and development, fiber length (both L and SFC) showed a significant correlation with cumulative DD during squaring -25 DAA while fiber maturity and fineness (FIN) was significantly correlated with cumulative LCS during anthesis-45 DAA. Increasing light interception in the canopy may improve boll production and fiber quality of cotton Quantitative relationship between subtending leaf irradiance and boll and fiber characteristics may be useful for developing predictive models of boll production and fiber quality in relation to light interception of cotton. |
หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Changes in Leaf Orientation and Canopy structure of Cotton (Gossypium hirsutum L.) under Different Plant Population Densities) ผู้เขียน:ดร.ศรปราชญ์ ธไนศวรรยางกูร, รองศาสตราจารย์, Herve Sinoquet, Eric Jallas, Michel Cretenet สื่อสิ่งพิมพ์:pdf AbstractThe effects of plant population density on diurnal changes of leaf orientation behavior and canopy structure of cotton (Gossypium hirsutum L.) during growing season were studied under field conditions by using an electromagnetic digitizing system for characterizing the canopy structure. At high density (80x9 cm-138,890 plants/ha), leaf area index (LAI) developed more rapidly than medium density (80x18 cm-69,440 plants/ha) and low density (80x40 cm-31,250 plants/ha), respectively, due to a greater number of leaves per plant. At the same plant age, plant characteristics, except leaf area plant and leaf area expansion rate (LAER), of high-density canopy differed from medium-density canopy while those expect leaf size differed from low-density canopy. Medium–density canopy did not show significant difference of plant characteristics compared to the low-density canopy, except leaf size and number of leaves per m2. At the same LAI stage, the cotton plants under high density had different plant characteristics, except leaf size and number of leaves per m2, from those under medium density. However, the plant characteristics, except internode length and number of leaves per m2, of high – and medium- density canopies did not differ significantly from low-density canopy. Leaf orientation behavior did not differ significantly between plant densities, particularly at the same stage of LAI. Cotton leaves tended to face the sun more at noon than in the morning and in the afternoon during growing season. Changes in horizontal and vertical distributions of leaf area were not significantly altered during the day by diurnal leaf orientation, but they differed significantly during growing season. These changes were significantly different between the three plant population densities at the same plant age. However, there were no significant differences in horizontal and vertical leaf area distribution at the same stage of LAI among the three plant population densities. This quantitative description of canopy structure may be useful for developing mathematical models of light interception in the canopy of cotton. |