Thai Agricultural Research Journal

Nitrogen Response and Uptake of Sweet Corn Grown on Clay Loam Soil

Chattanaporn Kueanoon — 2024-04-29

Suitable nitrogen fertilizer management can increase yields and reduce chemical fertilizer uses but the existing nitrogen fertilizer recommendation for sweet corn production is not appropriate for site-specific recommendation. This study aimed to investigate nitrogen response and uptake of sweet corn grown on clay loam soil at Uthai Thani province in 2017. Treatments were laid out in a randomized complete block (RCB) with four replicates. The treatments consisted of six levels of nitrogen at the rates of 0, 8, 16, 24, 32 and 40 kg N/rai, while fertilizer application for phosphate and potash was 1.0 times of the soil test recommended rate. Results showed that the response of unhusked ear weight (Y) of Hybrix 3 cultivar to nitrogen application rate (x) grown in clay loam soil with low soil organic matter (1.34%) at Uthai Thani province could be expressed as a quadratic equation, by Y=-0.6989x²+44.985x+2803; R²=0.9106. Moreover, the result of economic return analysis by VCR method showed that nitrogen fertilizer application at the rate of 16 kg N/rai could maximize the highest return. The amounts of total nitrogen uptake in plant were 25.7, 3.7 and 23.7 kg N, P and K/rai, respectively, while the amounts of total nitrogen lost by yield removal were 10.6, 1.8 and 7.8 kg N, P and K/rai, respectively. Using proper rate of nitrogen fertilizer can efficiently increase yield of sweet corn grown on clay loam soil at Uthai Thani province.

Variability of Pyricularia oryzae Populations Causing Agents of Rice Blast in Thailand

Oraya Phanon — 2024-04-29

Rice blast, caused by Pyricularia oryzae, is an important disease of rice production in Thailand. This disease is distributed in all localities of the country. It affects the quality and quantity of rice production. The purpose of this research was to evaluate the variation of P. oryzae populations collected from major rice growing areas of the country by studying their pathogenicity towards 9 differential rice varieties that had single resistance genes (near isogenic lines; NILs): Pi-7(t), Pi9, Pi-a, Pi-b, Pi-i, Pi-kh, Pi-t, Pi-ta and Pi-sh. Results revealed that from the 80 isolates studied, the pathogen could be identified into 47 races. When all isolates were clustered by UPGMA methods Past 4.10 program by using disease index data, the classical clustering analysis showed that P. oryzae races were grouped into 13 clades with cophenetic correlation at 0.80. However, race identification and clustering were not correlated with the sources of P. oryzae, more than one race could occur in one site. The results indicated that pathogenicity of the fungus was variable within the population as well as among populations. These results were informative for the planning of improvement of blast disease resistant rice varieties.

Physiological Race Profile of Xanthomonas oryzae pv. oryzae Isolated from the Rice Ecosystem in Chiang Rai Province

Pairoh Khwanngam — 2024-04-29

This study investigated the diversity and distribution of the bacterial leaf blight (BLB) pathogen, Xanthomonas oryzae pv. oryzae (XOO) population in the diverse rice ecosystem of Chiang Rai province, Thailand. A total 274 XOO isolates were collected during 2016 to 2019 from 18 surveyed districts in the province. Representative isolates of each district were selected and physiological race analysis conducted on 11 near isogenic lines (NILs) with single BLB resistance genes. A total of 47 physiological races of XOO were identified, with the highest number of races found in Phan (26 races) and Chiang Saen (20 races). Rice with the xa5 resistance gene had broad-spectrum resistance to the pathogen population (76.3%), followed by Xa7 (62.4%), Xa21 (33.6%), and Xa11 (31.4%). Most of the isolates were in race 8 (SSSRRSSSSSS) (27.37%), followed by race 27 (SSSRRSSSSSR) (12.41%), and race 17 (SSSSSSSRRSS) (10.22%). Sixteen races were found to be able to infect NILs with the xa5 gene, and these isolates were isolated from rice varieties RD6 and KDML 105 in Phan and Chiang Saen districts. The 47 races were grouped into three clusters based on the similarity coefficient of the reaction response on rice with BLB resistance genes. The number of isolates and the effective controlling gene in cluster 1, 2, and 3 were 74 (xa5), 170 (xa5), and 30 (xa5 and Xa7) isolates, respectively. This study provides valuable information on the diversity and distribution of XOO races in Chiang Rai province, which can be used to manage new rice resistant cultivars for a sustainable controlling of BLB.

Wastewater from Tapioca Starch Manufacturers Affecting Growth and Yield of Sugarcane

Jureeporn Keabpimai — 2024-04-29

The severe drought crisis in Thailand, which has been intensifying since the end of 2019 continuously resulting in water shortages. Therefore, utilizing industrial wastewater for beneficial purposes has been one of the strategies to address the drought problem. This research aimed to study the impacts of effluent wastewater from tapioca starch manufacturers on the growth and yield of sugarcane, comparing it with natural water and rainfed conditions. The quality of the effluent wastewater from the tapioca starch factory was assessed, revealing that the levels of total suspended solids (TSS), total dissolved solids (TDS), initial biochemical oxygen demand (BOD), and chemical oxygen demand (COD) exceeded the prescribed standard for discharge of tapioca starch effluent wastewater. The growth and biomass of sugarcane var. KhonKaen 3 were examined to investigate the effect of supplying effluent wastewater. The experimental design of the plot followed a randomized complete block design (RBD) with four replications and three treatments. The treatments included: 1) Supplemental water using factory effluent wastewater, 2) Supplemental water using natural water, and 3) No water (rainfed condition serving as the control) weekly measurements of crop water uptake for sugarcane var. KhonKaen3 was recorded and calculated based on crop water requirements handbook. The effect of water supply on sugarcane cultivation revealed no significant differences in growth and sugarcane yields including stem height (257.8-270 cm.), length of internode (8.38-8.94 cm.), number of internodes/stem (26.83-27.08 internodes/stem), weight/stem (1.85-1.87 kg/stem), and yield/rai (16.96-17.30 tons/rai) between the supply of factory effluent wastewater and natural water supply. The application of rainfed supply resulted in a decrease in both growth and sugarcane yield. However, the percentage of CCS (commercial cane sugar) exhibited no statistically significant difference across the treatments (12.38-13.40 °Brix). After harvesting, the accumulated levels of toxic substances and heavy metals in sugarcane and soil samples remained within the acceptable standard limits. The analysis of soil samples revealed relatively elevated levels of nutrient element accumulation, including potassium, calcium, magnesium, manganese, and iron, which remained below the standard value. Nonetheless, the extent of toxic substance accumulation in the soil is contingent upon the duration of the plantation period. In primary conclusion, the findings suggest that the effluent wastewater from the tapioca starch industry holds promise for plant cultivation during a drought crisis, as it does not exhibit any significant adverse effects on plant yields and soil quality.

Planting Methods Affecting Soybean Yields Grown after Rice

Sopit Jaipala — 2024-04-29

Soybean cultivation in dry season is mostly done in irrigated areas and was planted in the field after harvesting rice. There are various of soybean planting methods. Different methods are suitable for areas with different plot preparations. The objective of this experiment was to investigate the most suitable planting method of soybean after rice production to obtain the highest yield and value for investment. The experiments were conducted at the Chiang Mai Field Crops Research Center in the dry season during 2018 - 2020. Chiang Mai 60 variety was used in this experiment. Randomized complete block design with 4 replications was set and different planting methods were arranged as treatments; 1) recommended method (pushing planting hole method), 2) pecking wheel method, 3) sowing method, 4) recommended + rice straw mulching methods, 5) pecking wheel + rice straw mulching methods, and 6) sowing + rice straw mulching methods. The results from combined analysis of yield from 3 years revealed that different planting methods was significantly affected soybean yield and growth. It was found that recommended + rice straw mulching methods, pecking wheel + rice straw mulching methods and sowing + rice straw mulching methods gave no difference in yields (447-449 kg/rai). These three methods, however, attained a significantly higher yield than the other methods tested. The increasing of number of pods/plant was a major yield component responsible for yield increase. The worth investment (benefit cost ratio, BCR) of all treatments were 1.06-1.66. The method of sowing followed by rice straw mulching had the highest value in terms of investment.

Enzyme Production of Trichoderma spp. Isolated from Soil and Mushroom Spawn

Payungsak Rauyaree — 2024-04-29

Twenty-nine isolates of Trichoderma spp. obtained from soil and mushroom spawn samples during 2019 to 2021 were used to evaluate their degrading-enzymes synthesis efficiency on selective media. Degrading-enzymes synthesis efficiency was done by zone clearing technique and by calculating hydrolysis capacity (HC) value. The results revealed that isolates T-1, T-14 and T-22 showed the highest efficiency to synthesize pectinase, cellulase and amylase enzymes at HC values of 7.73, 7.13 and 5.00 respectively. Isolates T-1, T-14 and T-22 were identified by ITS4 and ITS5 gene sequencing. The results showed that T-1, T-14 and T-22 were Trichoderma asperellum (Samuels) Lieckf. & Nirenberg with 100, 99 and 99% identity. T-1 and T-14 were isolated from soil in Photharam, Ratchaburi province and Dan Makham Tia, Kanchanaburi Province respectively. Whereas, T-22 was isolated from mushroom spawn in Damnoen Saduak, Ratchaburi Province.

Genome Wide Association Study (GWAS) for Southern Corn Rust (SCR) Disease Resistance in Maize

Nay Nay Oo — 2024-04-29

Southern corn rust (SCR), caused by Puccinia polysora Undrew, is one of the most important maize diseases threatening maize production. Growing resistant varieties is the most practical and cost-effective approach to controlling the disease. Identification of resistance genes would help in the development of high-yielding resistant maize hybrids. Genome-wide association studies (GWAS) can efficiently reveal genomic loci associated with the desired phenotypic traits. In this study, the phenotypes of 262 maize recombinant inbreds against two isolates of SCR disease, namely, Nakhon Pathom and Chiang Mai, were investigated. Using 434,871 single nucleotide polymorphism (SNP) markers obtained from the maize SNP 600K genotyping array, GWAS was performed with the Fixed and random model Circulating Probability Unification (FarmCPU) model. The results showed that 19 SNPs distributed on chromosomes 1, 2, 3, 4, 5, 9 and 10 were significantly associated with resistance to SCR disease. As a result, 19 quantitative trait loci (QTL)s and 36 candidate genes were identified. In addition, the three major QTLs/SNP loci which included AX-90915192 on chromosome 4, AX-91151225 on chromosome 9 and AX-91648757 on chromosome 5, could distinguish the disease-resistant from disease-susceptible lines. These identified SNPs and genes provide useful information for cloning genes and understanding disease resistance mechanisms to SCR, and can be used in marker-assisted breeding programs to develop SCR resistant maize.

Path Analysis of Fresh Fruit Bunch and Bunch Weight in Oil Palm

Surakitti Srikul — 2024-04-29

Income of oil palm planters comes from the quantity of fresh fruit bunch (FFB) combining with the bunch weight harvested. This study focused on the direct and indirect effects of fresh fruit bunch and bunch weight using path analysis. Ninety tenera oil palm bunches were counted, weighed and individually separated. The results showed that bunch number (BNO) was a factor effect directly more than the average bunch weight (ABW), while a negative correlation was found between BNO and ABW, confirming that if the number of bunches was high, the ABW was small. Bunch weight (BW) composed of 9 characters interesting in this study: rachis weight per bunch (RCIS/B), rachillae weight per bunch (RCHAE/B), fruit weight per bunch (FW/B), fruit to bunch (FTB), mesocarp to fruit (MTF), kernel to fruit (KTF), shell to fruit (STF) and mean nut weight (MNW) were highly significant. Bunch weight (BW) was used to determine which components were effective. Fruit weight per bunch (FW/B) had the highest direct effect, followed by rachillae weight per bunch (RCHAE/B). Therefore, BNO and FW/B were selected to focus on fresh fruit bunches in the oil palm breeding programs.

Hot Water Immersion Treatment of Nam Dorkmai Mango Infested with Oriental Fruit Fly, Bactrocera dorsalis (Hendel), for Export

Sunyanee Srikachar — 2024-04-29

Hot water immersion treatment is a post-harvest treatment for fruit fly disinfestation and widely used as quarantine treatment in many countries. This technique has not been previously employed in Thai mango exports. The objectives of this research were to examine optimum temperature and exposure period of hot water immersion treatment to eliminate fruit fly, Bactrocera dorsalis, eggs and 1^st instar larvae in mango variety Nam Dorkmai without affecting fruit quality. Procedures for hot water immersion treatments in small and large scale were arranged. Nam Dorkmai mangoes used for testing were infested with B. dorsalis, eggs or 1^st instar larvae using artificial infestation and forced infestation methods. The results showed that hot water immersion treatment at the innermost of fruits at 46° C for 10 minutes was effective for elimination of both eggs and 1^st instar larvae of B. dorsalis without impacting on fruit quality. This information can be applied to quarantine process of B. dorsalis infestation in exported Nam Dorkmai mangoes of Thailand.