Modern Plant Breeding For Sustainable Agriculture: A Review

More foods are required to fulfill human need. The limitation of the farming area is leading to intensification system in crop cultivation, so the use of chemical properties and environmental destruction cannot be denied. However, this industrial practice in the crop system has caused many adverse effects on ecological balance and human health. Many severe impacts of industrial agriculture practices have been reported, including soil erosion, groundwater contamination, loss of productivity, depletion of fossil resources, air pollution, new threats to human health and safety. Many experts agreed that sustainable agriculture seems to be an effective way to solve these issues. Modern plant breeding is now a popular approach to provide superior crop cultivars that can minimize adverse effects of agriculture practices because humans can recognize and manipulated genes through this method. Recently, the application of molecular markers in plant breeding selection has been brought enthusiasm for plant breeders. Marker-assisted selection (MAS) has been evidenced to be a beneficial technique in plant breeding. Through this approach, the selection process of parents and progenies in the breeding process could be more efficient. Plant breeding is influential in crop production achievement because this effort is connected with the adaptability and stability of the varieties in many different environmental circumstances. Plant breeding also focuses on agriculture sustainability due to its effort to produces durable disease resistance, abiotic stress tolerance, nutrients, and water-use efficiency

Interaction of Predatory Ladybird Beetle, Micraspis discolor with Nilaparvata lugens throughout Paddy Growing Seasons

Coccinellidae is a high-interest family that has performed well and is widely distributed. It is valuable in economic service because it acts as an agricultural biological control agent. The Micraspis discolor (Syn=Verania) (Coleoptera: Coccinellidae) is a successful omnivorous predator in rice ecosystem and functions well as a general biological control for maintaining the population of brown planthopper (BPH) (Nilaparvata lugens), the major rice pest worldwide. Studies of natural enemies’ abundance are necessary to increase the practical use of biological control in agriculture. This study investigated the abundance correlation of M. discolor (prey) and rice pest N. lugens (prey) from two different geographical areas of rice fields in west and south Peninsular Malaysia. The cyclone lightrap and sweep net method succeeded in collecting 185 individuals of M. discolor and N. lugens. The study indicated that M. discolor, and the N. lugens collected from Selangor were more numerous than Johor in the ripening phase than in the reproductive and vegetative phases.  M. discolor can be found in all stages of rice growth. There are positive correlations between M. discolor and N. lugens in both localities throughout the rice growing season. The positive correlation highlighted that the number of pests has increased parallel to the number of predators and vice versa.  The use of M. discolor as a predator is essential in agriculture, along with the treatment of a healthy ecosystem landscape of diverse vegetation combinations, which helps to reduce the use of pesticides

Morpho-physiological screenings and molecular analysis of west sumatra rice genotypes under submergence stress

This study investigates the submergence tolerance level of 14 rice genotypes by morpho-physiological and molecular analyses of Sub1 alleles. IR64-Sub1 was used as a submergence tolerant check. The submergence screenings were conducted by submerging 14-days-old seedlings in water tanks for 14 days while molecular analysis was conducted using 14 Sub1 linked markers. The results showed that 5 tested genotypes, namely Inpari 48 Blas, Mundam Putiah, Batang Piaman, Banang Pulau and Pulau Sijunjung, recorded high survival rates (SR) of 80% to 100% under submergence stress. PCR-based identification of the Sub1 alleles confirmed that several tested genotypes carry Sub1A and Sub1C, but not all were expressed in their phenotypic performance towards submergence. IR64-Sub1 and Batang Piaman not only showed well-adaptation towards submergence by maintaining lower elongation (<20%) and less chlorophyll content change (TCC) (<30%) but were also equipped with the Sub1A allele. These genotypes potentially provide good phenotypic and genotypic performance under submergence stress conditions. Additionally, based on population structure analysis, these genotypes were grouped into 3 clusters, of which 35.71% are pure accessions, while the remaining 64.29% have admixture ancestry between populations 1, 2 and 3. The data in model-based population structure and UPGMA dendrogram supported that rice genotypes in this study have 3 well-differentiated genetic populations and admixtures. Most genotypes have a close genetic relationship with Nei’s similarity index ranging from 0.571 to 0.893

Morphological variations of weedy rice (Oryza sativa ssp.) in selected rice fields of Peninsular Malaysia

Weedy rice or locally known as ‘padi angin’ has been infesting rice granary areas in Malaysia for the last 20 years. The outbreak of weedy rice in the country started during the late 1980s in Projek Barat Laut Selangor (PBLS) due to the adoption of direct-seeding practices. Weedy rice can be characterized by its early maturing and easy-shattering traits. The objective of this study was to determine the morphological variations of weedy rice in selected granary areas located in Peninsular Malaysia. A total of 110 weedy rice accessions were collected from nine locations in three granary areas in Peninsular Malaysia (the Western, Eastern, & Northern regions). The collected weedy rice accessions were planted under greenhouse conditions to study their morphological features. Results of the present study indicated that 73.6% of weedy rice accessions were awnless while the remaining 26.4% produced awn. Selected traits such as plant height, flag leaf length, culm length, number of tillers, number of panicles, and panicle length were included in the Principal Component Analysis (PCA). The weedy rice accessions were grouped into three different clusters mainly Cluster 1: cultivated rice and awnless populations, Cluster 2: brown and red pericarp awnless populations, and Cluster 3: awned populations. The findings of this study may be used as guidance for farmers and researchers for designing sustainable weedy rice management in the future

Genetic variability of oil palm (Elaeis guineensis Jacq.) deli dura inter-crosses population in the MPOB research station Hulu Paka, Terengganu, Malaysia

The oil palm Deli dura breeding population is the most widely used dura for breeding and seed production. Due to its narrow genetic base, with current material originating from the four initial dura palms of Bogor, the Deli dura is presumed to have low genetic diversity. A total of 35 MPOB Deli dura inter-crosses from eight paternal parents were characterized based on 22 different traits including bunch yields, bunch quality components, as well as other vegetative and physiological traits. Based on the principal component analysis of the collected data, the first five components (PC1-PC5) possessing eigenvalues surpassing 1, contributed to 97.83% of the overall variance. PC1, with the highest variation (30.88%), was characterized mainly by vegetative and physiological traits, while PC2, with about 26.02% variation, was primarily associated with bunch quality components. The principal component score plot suggests that populations of the Johor Labis paternal parents 0.278/318 and 0.278/295 are unique populations and can be used in further breeding programmes. Besides, the populations from Ulu Remis (0.280/68) and Ulu Remis × Elmina (0.281/44) paternal parents were positively associated with PC2, suggesting strong performance in bunch quality components. Cluster analysis indicated that all populations were clustered into three main groups comprised of several sub-clusters, with populations of paternal parents 0.279/48 (Banting) and 0.281/74 (Banting) were outliers in the second and third clusters, respectively. In overall, the study revealed the presence of variation among the Deli dura inter-crosses based on the traits evaluated. These results will be useful for the selection of specific populations for genetic improvements of bunch yield, bunch quality, as well as vegetative and physiological characteristics

Heat stress in vegetables: impacts and management strategies - a review

Global climate change has not only caused a significant rise in the average temperature around the world but has also threatened crop productivity and food security. Heat stress disrupts various plant physiological and biochemical processes, such as inhibition of growth and development, reduction of photosynthesis rate and nutrient uptake, consequently causing yield losses. The destructive effects of heat stress are expected to worsen in the coming years. Thus, it has become imperative to understand how vegetables respond and adapt to heat stress in order to improve their heat tolerance ability. Various approaches have been adopted to enhance heat stress tolerance in vegetables, including modifying cultural practices and crop improvements through several breeding methods. This review gives comprehensive and up-to-date information on the effects of heat stress on vegetables; and existing as well as emerging methods adopted to enhance heat tolerance in vegetables. It also provides a brief overview of a new method called speed breeding, which can be leveraged to fast-track the breeding process for developing heat stress-tolerant vegetables

Carbon-Ion beam radiosensitivity study and biological responses of high-yieldingrice line, MR219-PL-5

The carbon ion-beam has emerged as a novel physical mutagen for creating genetic variability and crop improvement. In this study, seeds of a high-yielding pyramided rice line MR219-PL-5 were exposed to carbon ion beam irradiation at 10, 20, 40, 60, 80, and 100 Gy. The radiosensitivity test was conducted to determine the optimum dose of carbon ion beam irradiation based on the lethal dose 50% (LD50) using Sandwich Blotter Technique. The biological responses of carbon-ion beam irradiation were also observed in other characteristics such as germination rate (GeR), survival rate (SR), growth rate (GRoR), shoot length (SL), root length (RL), seedling height (SH), days to flowering (DTF), fertility rate (FR) and thousand-grains weight (TGW). Based on the polynomial curve of SR graph, the lethal dose 50% (LD50) value was 86.12 Gy. However, the optimum dose range of carbon ion-beam irradiation was between 40 and 60 Gy as these two doses recorded the highest SR, 63 and 67%, respectively. Furthermore, the shoulder dose in this study was 60 Gy since SR decreased significantly at higher doses. M1 individuals irradiated at 40 and 60 Gy had the best biological responses where significant differences were found for SR, SL, RL, GRoR, SH, DTF and FR at these two doses compared to the other doses. Further studies on M2 and M3 populations could help to identify potential individuals as well as to understand the inheritance of each trait of interest from one generation to the next

Susceptibility of Malaysian Rice (Oryza sativa L.) Cultivar to Saline Water Submergence Based on the Morphological Traits

Saline water submergence is a newly emerge abiotic stress jeopardizing rice production especially for the rice fields located nearby or alongside coastal areas. The stress was caused by the intrusion of sea water into those rice fields causing flash flood mainly during monsoon season. The present study was conducted to evaluate susceptibility level of selected Malaysian rice cultivars to saline water submergence at seedling stage based on the morphological traits and survival rate. There were six genotypes involved in the study mainly IR64-Sub1 as submergence tolerant control, Pokkali as salinity tolerant control, IR64 as susceptible control and MR297, MR284 and MR253 as local rice cultivars, respectively. The experiment was conducted using split plot design with three replications. On the day 14 after germination, all rice seedlings were totally submerged of about one-meter depth in a polyethylene tank containing saline water at 0, 4, 8 and 12 dS/m for 14 days while the non-submerged plant was control of the experiment. Seedling growth attributes and survival rate were recorded before, right after de-submerged and 14 days after de-submerged. All genotypes however were susceptible to saline water submergence at 4, 8 and 12 dS/m. In contrast, under 0 dS/m, IR64-Sub1 recorded significantly higher survival rate at 83% as compared to MR284 (17%), MR297 (17%), Pokkali (8%), MR253 (0%) and IR64 (0%).  All genotypes were not survived under saline submergence. Therefore, further phenotypic screening of rice genetic resources originated from or nearby coastal areas could be suggested in order to increase chance of identifying potentially tolerant genotype to saline water submergence

Drought-induced changes in the flowering capacity, anthesis quality and seed set in rice (Oryza sativa L.)

Drought stress significantly reduces grain yield (GY) due to poor spikelet fertility and anthesis quality. Aim of this study was to understand the changes of flowering capacity, anthesis quality traits and seed set in the re-watered drought stressed modern high yielding drought susceptible rice cultivar, IR64 at heading (DSH) and booting (DSB) stages. The wellwatered plants served as control of the experiment. Results obtained suggest that spikelet moisture content at above 80% was required to maintain optimum anthesis process in rice. Anthesis process in DSH plant was suspended when leaf relative water content (LRWC) dropped to below than 70%. Effects of drought stress on the spikelet moisture were irreversible as compared to the leaf rolling and LRWC. Hence, seed set was failed to occur at the upper rachis branches of the DSH plant. Anthesis process in the re-watered drought stress plants was resumed on the third day after re-watering with about 50% and 80% of anthers managed to dehisce in the DSH and DSB plants. Consequently, percentage of spikelet fertility and seed set in the DSH and DSB plants were increased towards the lower parts of the panicle. The GY, number of seeds, spikelet fertility, and harvest index however were significantly lower in the DSH plant (0.30 g, 13, 16.40%, and 14.81) as compared to DSB plant (1.34 g, 57, 59.14%, and 48.30), respectively. In addition, all interrelated traits involved in the flowering process of rice could be collectively termed as the anthesis quality traits due to their significant correlation with the grain yield and other yield components

Response of primed rice (Oryza sativa L.) seeds towards reproductive stage drought stress

Seed priming could be promoted as a potential alternative in alleviating drought stress challenges in rice cultivation. The present study was conducted as an attempt to verify potential performance of seed priming in improving seedling growth and harvestable grain yield of rice under reproductive stage drought stress (RS). Seed treatments involved were non-primed seeds as control (T1), hydro-primed (T2) and osmo-primed at -1.0 mPa with polyethylene glycol (PEG6000) (T3). Reproductive stage drought stress (RS) was imposed at soil water potential lower than -60 kPa. The well-watered plants served as control of the experiment. In general, seedling growth of T3 was better than T2 and T1 for all growth parameters in both planting seasons. Yield components were significantly lower in RS as compared to well-watered treatment (WW). The agronomic performance of primed seeds in T2 and T3 were not significantly different with T1 under both RS and WW for both planting seasons. As a conclusion, seed priming treatments used in this study was ineffective in improving agronomic performance of rice under RS. Therefore, other alternatives such as development of drought tolerant rice should be highly emphasized in order to minimize the impact of drought on growth and yield of rice plant