Available cloned genes and markers for genetic improvement of biotic stress resistance in rice

Biotic stress is one of the major threats to stable rice production. Climate change affects the shifting of pest outbreaks in time and space. Genetic improvement of biotic stress resistance in rice is a cost-effective and environment-friendly way to control diseases and pests compared to other methods such as chemical spraying. Fast deployment of the available and suitable genes/alleles in local elite varieties through marker-assisted selection (MAS) is crucial for stable high-yield rice production. In this review, we focused on consolidating all the available cloned genes/alleles conferring resistance against rice pathogens (virus, bacteria, and fungus) and insect pests, the corresponding donor materials, and the DNA markers linked to the identified genes. To date, 48 genes (independent loci) have been cloned for only major biotic stresses: seven genes for brown planthopper (BPH), 23 for blast, 13 for bacterial blight, and five for viruses. Physical locations of the 48 genes were graphically mapped on the 12 rice chromosomes so that breeders can easily find the locations of the target genes and distances among all the biotic stress resistance genes and any other target trait genes. For efficient use of the cloned genes, we collected all the publically available DNA markers (~500 markers) linked to the identified genes. In case of no available cloned genes yet for the other biotic stresses, we provided brief information such as donor germplasm, quantitative trait loci (QTLs), and the related papers. All the information described in this review can contribute to the fast genetic improvement of biotic stress resistance in rice for stable high-yield rice production

Available cloned genes and markers for genetic improvement of biotic stress resistance in rice

Biotic stress is one of the major threats to stable rice production. Climate change affects the shifting of pest outbreaks in time and space. Genetic improvement of biotic stress resistance in rice is a cost-effective and environment-friendly way to control diseases and pests compared to other methods such as chemical spraying. Fast deployment of the available and suitable genes/alleles in local elite varieties through marker-assisted selection (MAS) is crucial for stable high-yield rice production. In this review, we focused on consolidating all the available cloned genes/alleles conferring resistance against rice pathogens (virus, bacteria, and fungus) and insect pests, the corresponding donor materials, and the DNA markers linked to the identified genes. To date, 48 genes (independent loci) have been cloned for only major biotic stresses: seven genes for brown planthopper (BPH), 23 for blast, 13 for bacterial blight, and five for viruses. Physical locations of the 48 genes were graphically mapped on the 12 rice chromosomes so that breeders can easily find the locations of the target genes and distances among all the biotic stress resistance genes and any other target trait genes. For efficient use of the cloned genes, we collected all the publically available DNA markers (~500 markers) linked to the identified genes. In case of no available cloned genes yet for the other biotic stresses, we provided brief information such as donor germplasm, quantitative trait loci (QTLs), and the related papers. All the information described in this review can contribute to the fast genetic improvement of biotic stress resistance in rice for stable high-yield rice production

ENVIRONMENTAL EFFECT ON BIOTIC STRESS AND RESPONSE OF BREAD WHEAT (TRITICUM AESTIVUM L.) GENOTYPES UNDER RAINFED CONDITION

Wheat is one of the most important crops in the world with the largest production of any crop owing to its ability to adapt to environmental conditions. Bread wheat, a major cereal crop, is subject to several biotic stresses. These stresses affect the crop’s yield, quality and yield components. Different mechanisms have been adopted by plants to counter the wide range of biotic and abiotic stresses faced. Leaf rust (Puccinia triticina), stripe rust (Puccinia striiformis f. sp. tritici), septoria leaf blotch (Septoria tritici), and powdery mildew (Blumeria graminis f. sp. tritici) are mainly and widespread imported diseases of wheat in the Trakia region, Turkey. This research was established with 25 genotypes in RCBD with 4 replications, and four environments in the Trakia region, in the 2017-2018 growing seasons. According to the result, there were significant differences among genotypes for yield and biotic stress factors. The mean yield of the genotypes was 6161 kg ha-1, the highest yield was determined in G21 (6807 kg ha-1) and Köprü (6776 kg ha-1). The lowest infection was observed in the Keşan location. G9 highly was tolerant or highly resistant to leaf rust across four environments. Genotypes G17, G19, and G24 were highly tolerant to LR showed 0-TR reaction across four environments. It was no observed any stripe rust infection in ten genotypes, and six genotypes showed a 0-TR reaction. Because of the lowest infection, there was almost no negative association between grain yield and leaf rust in Edirne and Keşan location but in Tekirdağ and in Lüleburgaz location there was a slightly negative relationship between grain yield and leaf rust. Stripe rust infection was low due to unfavourable environmental conditions and it was not observed in ten genotypes. G7 was tolerant to septoria leaf blotch and four genotypes (G7, G18, G19 and G25) were highly tolerant to powdery mildew across four environments under rainfed conditions

EFFECTS OF GAMMA RADIATION ON GERMINATION AND PHYSIOLOGICAL PARAMETERS IN BREAD WHEAT (TRITICUM AESTIVUM L.) GENOTYPES

This research was carried out to determine the effects of gamma radiation on germination and physiological characteristics of bread wheat genotypes. Eight bread wheat genotypes were irradiated with 175, 200, 250 Gy gamma-ray. Physiological parameters were recorded in the M1 population for flag leaf area, days of heading, some stomata, chlorophyll content at three growth stages, and biomass (NDVI) at five growth stages. The results showed that flag leaf area (cm2), biomass (NDVI), chlorophyll content (SPAD) decreased with increasing gamma irradiation doses but days of heading increased. The data showed that in comparison with the control population germination in mutagen-treated population was less than over the control population. NDVI was taken in the control treatment and M1 mutant lines at five growth stages and NDVI in the mutagen treated population was less than over the control population. Flag leaf area varies widely as a consequence of its interaction with the genotypes of treatment factors. The highest flag leaf area was determined in the control treatment (21.85 cm2) and increasing in gamma irradiation level lowered flag leaf area (15.70 cm2) in M250 Gy gamma irradiation. Control treatment had higher chlorophyll content and an increase in the dose of gamma rays reduced the chlorophyll content of genotypes scaled at Z30, Z45, and Z55 growth stages. It can be seen that days of heading increased with an increasing dose of mutagen treatments. Days of heading in the control treatment were 145.12 days and 154.75 days in mutagen 250 Gy gamma dosses. Based on mean value genotypes BBVD7-2014 had a higher flag leaf area (22.98 cm2), followed by BBVD22-2016. The highest chlorophyll content was determined in BBVD22-2016 and Saban. Cultivars Anafarta and Abide had higher biomass (NDVI). In conclusion, gamma radiation could be useful for the alteration of physiological characters. Mutation breeding (gamma irradiation) is also a significant breeding tool that has been used successfully in several crops for breeding physiological and morphological traits

Biological Control Potential of Native Entomopathogenic Nematodes against the Potato Tuber Moth, Phthorimaea operculella (Zeller) (Lepidoptera: Gelechiidae) in Turkey

Abstract.-The biocontrol efficiency of three Turkish isolates of the entomopathogenic nematodes Steinernema carpocapsae, S. feltiae and Heterorhabditis bacteriophora were evaluated against the last instar of potato tuber moth (PTM) Phthorimaea operculella under laboratory conditions. To determine optimum nematode application rate and temperature, the experiments were conducted with 100, 500 and 1000 IJs at 10, 15 and 25 o C. Temperature and nematode concentration had a significant effect on P. operculella larval mortality. S. carpocapsae and H. bacteriophora species displayed generally increased virulence in parallel with rising temperature and the number of infective juveniles applied. At 25°C and 1000 IJs concentration, the larval mortality was 96 and 80% for S. carpocapsae and H. bacteriophora, respectively. However, S. feltiae did not exhibit more than 40% mortality at any temperature or concentration, except when the nematodes were applied in infected insect host cadavers. At 25°C, infected cadaver applications showed 97, 83 and 67% mortality for S. carpocapsae, H. bacteriophora and S. feltiae, respectively. Our results indicate that P. operculella larvae are quite susceptible to entomopathogenic nematode infection and, in particular, S. carpocapsae blacksea strain has a high level of potential to control this pest

COMPARISON OF AGRO-PHYSIOLOGICAL COMPONENT OF BARLEY (HORDEUM VULGARE L) GENOTYPES UNDER RAINFED CONDITION

This research was carried out to assess yield and agronomic and physiological parameters of barley genotypes under rainfed conditions. The experiments were set up with 25 barley genotypes in a completely randomized blocks design with four replications during the 2017-2018 growing cycle at two locations in Edirne and Tekirdağ in the Trakia region, Turkey. Grain yield, plant height, days of heading, peduncle length, spike length, spike number per square meter, kernel number per spike, spike weight, flag leaf area, NDVI, canopy temperature, chlorophyll content, 1000-kernel weight, test weight, protein ratio, grain uniformity were investigated. The results of the study showed that there were significant differences among genotypes based on investigated characters. The highest grain yield (8509 kg ha-1) was computed for the G22 line. Grain yield was positively slightly correlated with spike weight, kernel number per spike, NDVI (Z55), 1000-kernel weight, test weight, and grain uniformity but no correlated with flag leaf area. There was a significant positive relation with spike weight and flag leaf area, spike length and kernel number per spike. Flag leaf area positively significantly correlated with kernel number per spike, and slightly positively correlated with spike length. Biomass (NDVI) at Z55 growth stage had a positive direct effect on grain yield, spike weight, peduncle length, spike number per square meter, 1000-kernel weight, test weight, protein ratio and grain uniformity. A negative correlation was observed between canopy temperature with grain yield, spike number per square meter, plant height, biomass (at Z55), 1000-kernel weight, test weight, protein ratio and grain uniformity. Therefore, biomass and canopy temperature would be important selection criteria for improved grain yield and yield components in the breeding material studied

Comparative effects of entomopathogenic fungi and nematodes and bacterial supernatants against rice white tip nematode

Abstract The rice white tip nematode, Aphelenchoides besseyi, is the primarily important seed-borne pest of rice and was first recorded in Turkey in 1995. These biological agents, such as an entomopathogenic fungus (EPF), entomopathogenic nematodes (EPN), and bacterial supernatants, have been used against other plant parasitic nematodes but as far as not against A. besseyi. Accordingly, the EPF species, Purpureocillium lilacinum, and the four EPN species, Heterorhabditis bacteriophora, Steinernema carpocapsae, S. glaseri, and S. feltiae, and the supernatant of the two bacterial symbionts, Photorhabdus luminescens and Xenorhabdus bovienii, were used against A. besseyi. In addition, infected Galleria mellonella cadavers with S. feltiae were evaluated as a biological agent to the white tip nematode. The percentage of observed white tip symptoms, decrease in kernel numbers in the panicles, and decrease in panicle weight were evaluated. Evaluation of these parameters showed that X. bovienii supernatant, S. feltiae infective juveniles, and P. lilacinum at 108 conidia ml−1 consistently suppressed the A. besseyi population

EFFECT OF THE RAINFALL AND HUMIDITY AT VARIOUS GROWTH STAGE ON YIELD AND QUALITY IN BREAD WHEAT (TRITICUM AESTIVUM L.) CULTIVARS

High precipitation and humidity are mainly abiotic environmental factors may influence bread wheat quality during grain filling stages in Trakya region (Turkey). It was investigated effect of the rainfall and humidity, during growth stage Z24 and Z89, on yield, quality and some agronomic characters in bread wheat cultivars. Rainfall and humidity from shooting up to grain filling period were taken in experimental area. This research was established with 25 genotypes in RCBD with 4 replications in Edirne and Tekirdağ location, from 2011 to 2016 growing seasons. Grain yield, 1000-kernel weight, test weight, protein ratio, gluten, gluten index, hardness, sedimentation, plant height and days of heading were investigated. It was found various relations among locations and investigated parameters based on rainfall and humidity with yield and quality. The results showed that high rainfall from shooting up to grain filling stage had a negatively effect on protein ratio, gluten, gluten index and sedimentation in Edirne location. The high mean humidity from Z31 to Z89 growth stage had a positively effect on grain yield. Rainfall from shooting up to grain filling period had also positively effect on gluten index. Rainfall during Z24-30 and Z77-89 plant growth stage had positively effect on grain yield. At Tekirdağ location, rainfall during Z51-75 positively affected protein ratio (r=0.898*), and gluten value (r=0.714). High rainfall during Z77-90 growth stage negatively affected grain yield, 1000-kernel weight, and test weight. Humidity from Z24 up to Z89 growth stage had positively effect on grain yield, 1000-kernel weight and test weight. Mean humidity at Z51-75 and at Z77-89 growth stage led to significant reduction in gluten index. There was positively significant correlation between humidity with protein ratio and gluten value at Z51-75 and Z77-89 growth stage. All results showed that high rainfall and humidity have a various effects on quality and grain yield based on plant growth stage