ที่มา:วิทยาสารเกษตรศาสตร์ สาขา วิทยาศาสตร์

หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Identification of Nutrients Limiting Rice Seedling Growth in Soils of Northeast Thailand under Water-Limiting and Non-Limiting Conditions)

ผู้เขียน:ดวงใจ สุริยาอรุณโรจน์, Prasert Chaiyawat, Shu Fukai, Pax Blamey

สื่อสิ่งพิมพ์:pdf

Abstract

Glasshouse nutrient omission trials are useful in identifying nutrient limitations for plant growth in a number of soils under the same environmental conditions. Soils of low fertility are commonly used for production of rainfed lowland rice (Oryza sativa L.), and the crop often encounters water stress. Nutrient requirements may be modified when standing water disappears from the field. Two experiments with rice seedlings were conducted in a glasshouse at Ubon Rice Research Center, Thailand, to identify the nutrients which limit rice growth in soils of Northeast Thailand, and to determine whether nutrient limitations are affected by water availability. In Experiment 1, rice was grown on two soils (Roi Et and Ubon series) under well-watered and water-limiting conditions, and 15 nutrient treatments were imposed. In Experiment 2, six soils from Northeast Thailand were examined using the same 15 nutrient treatments. The nutrients which clearly limited the growth of rice plants in soils of Northeast Thailand were nitrogen (N) and phosphorus (P). In some cases, potassium (K) and sulfur (S) also limited growth, and in one soil zinc (Zn) and boron (B) also limited growth. A shortage of N was the most important limitation for plant growth in all soils except one in which P was more important. The low supply of P decreased plant height and leaf area development during early growth; low N supply had a greater effect later during growth. The omission of P had a larger detrimental effect on growth when water supply was limited. In the Roi Et soil, the omission of S had a large effect on leaf area and total dry matter production only under water stress conditions, but this was not found in the other soils examined. These results from glasshouse studies showed that the nutrients limiting rice growth depend on soil type and water availability in soils of Northeast Thailand.

Article Info

Agriculture and Natural Resources -- formerly Kasetsart Journal (Natural Science), Volume 034, Issue 3, Jul 00 - Sep 00, Page 323 - 331 |  PDF |  Page

ที่มา:วิทยาสารเกษตรศาสตร์ สาขา วิทยาศาสตร์

หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Effects of Drought Tolerant Quantitative Trait Loci on Flowering Traits, Panicle Exsertion Rate, Spikelet Sterility and Grain Yield of Rice under Rainfed Lowland Conditions)

ผู้เขียน:Rathmuny Then, Jonaliza L. SIANGLIW, ดร.อภิชาติ วรรณวิจิตร, ศาสตราจารย์, ดร.พูนพิภพ เกษมทรัพย์, รองศาสตราจารย์, Shu Fukai, ธีรยุทธ ตู้จินดา*

สื่อสิ่งพิมพ์:pdf

Abstract

Drought hinders rice production and yield stability in rainfed lowland ecosystems. Quantitative trait loci (QTL) for root traits on chromosomes 1, 2, 7 and 9 in backcross introgression lines (BIL) of elite rice variety IR64, derived from Azucena/IR64, were designated as Targets 1, 2, 7 and 9 in the present study. Severe stress developed during the period of optimum flowering as indicated by 98-100% yield reduction. Significant phenotypic variations in BIL were observed on days to flowering (DF), delay in flowering (DeF), panicle exsertion rate (PEX), percent spikelet sterility (PSS) and grain yield (GY). Variations among target QTL were also found in the traits studied, particularly under drought stress, indicating that BIL containing Targets 1 and 2 had early DF, higher PEX, lower PSS and higher GY under stress than those with Targets 7 and 9. Targets 7 and 9 lacked QTL for root thickness, indicating that it plays a role in drought tolerance under rainfed lowland conditions. Early flowering BIL had an advantage over later flowering ones because water can be extracted at the early drought stage, which can support the PEX and result in low PSS. In a very severe drought at the flowering stage, PSS directly affected GY. Further study of root morphology and early flowering under stress are necessary to improve rice yields under rainfed lowland conditions.

Article Info

Agriculture and Natural Resources -- formerly Kasetsart Journal (Natural Science), Volume 045, Issue 1, Jan 11 - Feb 11, Page 101 - 109 |  PDF |  Page