The population of brown plant hopper in paddy fields at Kedah / Aida Zabri

Brown planthopper (BPH) (Nilaparvata lugens) is one of the major insect pests that affect rice production in Kedah. The BPH attack caused the paddy field to have hopperburn phenomena which is the result of dried up of leaves. This study was conducted purposely to know the population of brown planthopper in paddy fields and the difference of the abundance of brown planthopper population in paddy fields between four provinces involved. The data of brown planthopper population was taken from Muda Agricultural Development Authority (MADA), which has four provinces under their management; Perlis, Jitra, Pendang and Kota Sarang Semut. The data collected consists of area affected by brown planthopper for three years starting from 2014 until 2016, which has two seasons for each year. This study shows that the area affected by brown planthopper population in Province 2, which is Jitra is the highest for all seasons. The outbreak of the brown planthopper in Jitra become the highest among all provinces due to the excessive pesticide and fertilizer application especially nitrogen on the paddy plant. Meanwhile, Province 1, which is Kangar is the least affected by the attack of brown planthopper population. However, this study shows that brown planthopper is not the major insect pest at the study area due to low percentage of total area affected

Low Association of Bph17 Allele in Landraces and Improved Varieties of Rice Resistant to Brown Planthopper

Resistance traits to brown planthopper on rice varieties are controlled by dominant and recessive genes called Bph/bph. Bph17 is one of dominant genes that control rice resistance to brown planthopper. Marker of Bph17 allele can be used as a tool of marker assisted selection (MAS) in breeding activity. Association of Bph17 allele and resistance to brown planthopper in Indonesian landraces and new-improved varieties of rice is not clearly known. The study aimed to determine the association of Bph17 allele in landraces and new-improved varieties of rice resistant to brown planthopper. Twenty-one rice genotypes were used in the study, consisting of 13 landraces, 5 improved varieties, 3 popular varieties and a check variety Rathu Heenati. Two simple sequence repeat markers linked to Bph17 allele were used, i.e. RM8213 and RM5953. The results showed that association of Bph17 allele in landraces and new-improved varieties of rice resistant to brown planthopper resistance was very low (r = -0.019 and -0.023, respectively). The presence of Bph17 allele did not constantly express resistance to brown planthopper. The study suggests that Bph17 allele cannot be used as a tool of MAS for evaluating resistance of landraces and new-improved varieties of rice to brown planthopper. Further research is needed to obtain a specific gene marker that can be used as a tool of MAS and applicable for Indonesian differential rice varieties

LOW ASSOCIATION OF Bph17 ALLELE IN LANDRACES AND IMPROVED VARIETIES OF RICE RESISTANT TO BROWN PLANTHOPPER

Resistance traits to brown planthopper on rice varieties are controlled by dominant and recessive genes called Bph/bph. Bph17 is one of dominant genes that control rice resistance to brown planthopper.  Marker of Bph17 allele can be used as a tool of marker assisted selection (MAS) in breeding activity. Association of Bph17 allele and resistance to brown planthopper in Indonesian landraces and new-improved varieties of rice is not clearly known. The study aimed to determine the association of Bph17 allele in landraces and new-improved varieties of rice resistant to brown planthopper. Twenty-one rice genotypes were used in the study, consisting of 13 landraces, 5 improved varieties, 3 popular varieties and a check variety Rathu Heenati. Two simple sequence repeat markers linked to Bph17 allele were used, i.e. RM8213 and RM5953. The results showed that association of Bph17 allele in landraces and new-improved varieties of rice resistant to brown planthopper resistance was very low (r = -0.019 and -0.023, respectively). The presence of Bph17 allele did not constantly express resistance to brown planthopper. The study suggests that Bph17 allele cannot be used as a tool of MAS for evaluating resistance of landraces and new-improved varieties of rice to brown planthopper. Further research is needed to obtain a specific gene marker that can be used as a tool of MAS and applicable for Indonesian differential rice varieties.

Higher Fertilizer Inputs Increase Fitness Traits of Brown Planthopper in Rice.

Rice (Oryza sativa L.) is the primary staple food source for more than half of the world's population. In many developing countries, increased use of fertilizers is a response to increase demand for rice. In this study, we investigated the effects of three principal fertilizer components (nitrogen, phosphorus and potassium) on the development of potted rice plants and their effects on fitness traits of the brown planthopper (BPH) [Nilaparvata lugens (Stål) (Homoptera: Delphacidae)], which is a major pest of rice in Bangladesh and elsewhere. Compared to low fertilizer inputs, high fertilizer treatments induced plant growth but also favored BPH development. The BPH had higher survival, developed faster, and the intrinsic rate of natural increase (r m ) was higher on well-fertilized than under-fertilized plants. Among the fertilizer inputs, nitrogen had the strongest effect on the fitness traits of BPH. Furthermore, both the "Plant vigor hypothesis" and the "Plant stress hypothesis" were supported by the results, the former hypothesis more so than the latter. These hypotheses suggest that the most suitable/attractive hosts for insect herbivores are the most vigorous plants. Our findings emphasized that an exclusive focus on yield increases through only enhanced crop fertilization may have unforeseen, indirect, effects on crop susceptibility to pests, such as BPH

IDENTIFICATION OF POLYMORPHISM ON SIMPLE SEQUENCE REPEATS MARKERS ASSOCIATED WITH BROWN PLANTHOPPER RESISTANCE GENES IN TWENTY RICE GENOTYPES AND THEIR GENETIC RELATIONSHIP

Brown planthopper is one of the most destructive insect pest of rice in Indonesia and other Asian countries. Pyramiding some brown planthopper resistance genes is a valuable approach to create more durable resistance against the pest. The objective of this study was to identify polymorphisms of Brown Planthopper Resistance genes (Bph) on 20 genotypes of rice, and to obtain genetic relationship among genotypes tested. The experiment was conducted from June to September 2012 at Green House and Laboratory of Plant Analysis and Biotechnology, Faculty of Agriculture, Universitas Padjadjaran, Jatinangor. Twenty genotypes were analyzed, and two of them were used as check varieties. Simple Sequence Repeat (SSR) markers were applied to detect Bph3, Bph4, Qbph3, and Qbph4 genes. Polymorphic levels were analyzed by calculating PIC (Polymorphic Information Content). The grouping of rice genotypes were done based on principal components analysis (PCA) of SSR data, and the genetic relationship based on the presence of Bph genes was estimated using UPGMA (Unweighted Pair Group With Arithmetic mean). Results showed that RM313, RM8072, RM8213, RM5953, RM586, and RM589 markers were polymorphic. Rice genotypes PTB 33, Diah Suci, Cibogo, Cisantana, Digul, Ciherang, Inpari 13, Inpari 10, and Memberamo had Bph3, Qbph3, Bph4, and Qbph4. Meanwhile Bph3, Qbph3, and Bph4 were supposed to be belonged by IR 64, Aek Sibundong, Batang Gadis, IR 66, and Mekongga. Kalimas and Tukat Penatu had Bph3, Qbph3, dan Qbph4. IR 74 had Bph3 and Qbph3, and Fatmawati had Bph3 and Bph4. UPGMA clustering resulted in two main clusters, in which the first cluster consisted of 2 subclusters. PTB-33 was closely related with Memberamo, Tukat Penatu, Digul, Diah Suci, and Kalimas. The SSR markers used in this study were proven to be valuable in molecular detection of Bph genes and in estimating genetic relationsips of rice genotypes. PTB-33 was a good donor of resistance genes, as well as Memberamo, Tukat Penatu, Digul, Diah Suci, and Kalimas which were identified as promising donors in rice breeding resistance to brown planthopper.Keywords : Bph gene, Brown Planthopper, Genetic relationship, SSR markers

Genetics of resistance of rice cultivar ARC10550 to Bangladesh brown planthopper teletype

Resistance to brown planthopper in rice cultivar ARC 10550 was found to be governed by a single recessive gene which was designated bph 5. It conveys resistance to brown planthopper populations in South Asia but not to the populations in East and Southeast Asia. This gene segregated independently of four other known genes for brown planthopper resistance. It should be possible to combine this gene with any of the other four genes to develop rice cultivars with a broad spectrum of resistance

Mapping and pyramiding of two major genes for resistance to the brown planthopper (Nilaparvata lugens [Stål]) in the rice cultivar ADR52

The brown planthopper (BPH), Nilaparvata lugens (Stål), is one of the most serious and destructive pests of rice, and can be found throughout the rice-growing areas of Asia. To date, more than 24 major BPH-resistance genes have been reported in several Oryza sativa ssp. indica cultivars and wild relatives. Here, we report the genetic basis of the high level of BPH resistance derived from an Indian rice cultivar, ADR52, which was previously identified as resistant to the whitebacked planthopper (Sogatella furcifera [Horváth]). An F2 population derived from a cross between ADR52 and a susceptible cultivar, Taichung 65 (T65), was used for quantitative trait locus (QTL) analysis. Antibiosis testing showed that multiple loci controlled the high level of BPH resistance in this F2 population. Further linkage analysis using backcross populations resulted in the identification of BPH-resistance (antibiosis) gene loci from ADR52. BPH25 co-segregated with marker S00310 on the distal end of the short arm of chromosome 6, and BPH26 co-segregated with marker RM5479 on the long arm of chromosome 12. To characterize the virulence of the most recently migrated BPH strain in Japan, preliminary near-isogenic lines (pre-NILs) and a preliminary pyramided line (pre-PYL) carrying BPH25 and BPH26 were evaluated. Although both pre-NILs were susceptible to the virulent BPH strain, the pre-PYL exhibited a high level of resistance. The pyramiding of resistance genes is therefore likely to be effective for increasing the durability of resistance against the new virulent BPH strain in Japan

Physical mapping of Bph3, a brown planthopper resistance locus in rice

Resistance to brown planthopper (BPH), a destructive phloem feeding insect pest, is an important objective in rice breeding programs in Thailand. The broad-spectrum resistance gene Bph3 is one of the major BPH resistance genes identified so far in cultivated rice and has been widely used in rice improvement programs. This resistance gene has been identified and mapped on the short arm of chromosome 6. In this study, physical mapping of Bph3 was performed using a BC3F3 population derived from a cross between Rathu Heenati and KDML105. Recombinant BC3F3 individuals with the Bph3 genotype were determined by phenotypic evaluation using modified mass tiller screening at the vegetative stage of rice plants. The recombination events surrounding the Bph3 locus were used to identify the co-segregate markers. According to the genome sequence of Nipponbare, the Bph3 locus was finally localized approximately in a 190 kb interval flanked by markers RM19291 and RM8072, which contain twenty-two putative genes. Additional phenotypic experiment revealed that the resistance in Rathu Heenati was decreased by increasing nitrogen content in rice plants through remobilization of nitrogen. This phenomenon should be helpful for identifying the Bph3 gene