Embryogenic Callus Formation in Local Cocoa (Theobroma Cacao L.) Clones

A study on the potential of embryogenic callus formation in KKM 1,KKM 15, KKM 17, KKM 22, KKM 27, KKM 28, PBC 123, PBC 159, MHP 78,MHP 79, MHP 296, AMAZ, GS 29, EET 339 and MJS 47 local cocoa clones which had been released by MARDI was carried out. A sigmoid curve for callus growth, viability and total protein content of stem, leaf, matured and immatured cotyledon derived callus were obtained. Based on this curve, the subculture interval was determined and it shows that the appropriate timing or period for subculture was between 20 to 24 days after the incubation. Obviously in this interval, the growth of callus was enormous and the total soluble protein was the highest. However, the viability was slowly decreased due to browning of the callus. Therefore only the white and friable callus was selected for subcultures. Embryogenic callus was successfully induced for PBC 123 and MHP 296 cocoa clones by using immature cotyledon derived callus. Negative results were obtained for all clones and explants tested using MS as the embryogenic induction medium but positive results were obtained for PBC 123 and MHP 296 clones using DKW and WPM basic media. The combinations of 2 mg/L 2,4-D and 0.25 mg/L Kin was the most successful auxin and cytokinin combination for embryogenic callus induction.. The nodular embryogenic callus of PBC 123 and MHP 296 emerged after the second subculture. Browning of callus occurred during incubation especially at the end of the culture period and was obvious for both clones. Enhancement of the embryogenic induction media by adding nitrogen rich compounds and amino acid such as casein hydrolysate, malt extract and proline did not improve the initiation of embryogenic callus. Instead, more friable callus were obtained from these enhanced media. In direct somatic embryogenesis, 15 cocoa clones had been tested and four clones showed positive results. These clones (MJS 47, GS 29, PBC 123 and PBC 159) were able to produce embryogenic callus from staminodes explants using the protocol previously developed by Li et al (1998). The nodular embryogenic callus of MJS 47, PBC 123, PBC 159 and GS 29 emerged at the cut ends and were transferred onto a secondary callus growth medium and continued to proliferate on this medium. Maturation of the embryogenic callus was carried out in a medium described by Li et al. (1998). The globular callus were pale brown in colour at the early maturation period but turned dark brown after 3 weeks of incubation period. None of the globular callus turned to heart shaped somatic embryo which is the second stage of somatic embryogenesis. The maturation of the globular callus was not achieved and the embryogenic callus became brown and turned non viable at the end of the incubation period. All embryogenic clones showed similar response to the maturation medium. Total soluble polyphenol content of embryogenic callus of PBC 123 after 16 days of incubation was 259.94 ± 15.53 μg/g fresh weight which was relatively lower than the non embryogenic callus (451.19 ± 5.42 μg/g fresh weight). The increment or accumulation of the TSP was almost similar in MHP 296 immatured cotyledon derived callus especially towards the end of the incubation period. Furthermore, the embryogenic callus which were induced from immature cotyledon of MHP 296 and PBC 123 showed high polyphenol accumulation as compared to embryogenic callus induced from staminode of GS 29, PBC 123, PBC 159 and MJS 47. The browning of non embryogenic callus was greater than embryogenic callus. The specific peroxidase activity was slowly increased as the callus became embryogenic. The POD activity was 164.27 ± 9.42 unit/mg protein for GS 29 embryogenic callus while for non embryogenic callus, the activity was around 63.31 ± 9.24 unit/mg protein at 16 days of incubation. Even though a similar pattern of increment could be observed between the embryogenic and non embryogenic callus, the POD activities was higher in embryogenic callus as compared to non embryogenic callu

Floral traits and flowering behaviors of Malaysia rice cytoplasmic male sterile and maintainer lines and its relationship with out-crossing performance

Rice is a strictly self-pollinating crop. However, in hybrid rice seed production, an effective male sterility system is used to produce hybrid seed in bulk. In hybrid rice system, the pollen grains of cytoplasmic male sterile (CMS) are sterile and the female organ of the CMS depends on the fertile pollen released by the maintainer or restorer lines via out-crossing or cross-pollination in order to produce seed. Floral trait and flowering behavior of CMS and its corresponding maintainer or restorer lines are essential factors in hybrid rice seed production because they influenced the out-crossing or cross-pollination between parental lines. Two local CMSs and their corresponding maintainer lines were developed through breeding program in Malaysian Agricultural Research and Development Institute (MARDI) namely 0025A/0025B and 0047A/0047B. This study was carried out on floral traits and flowering behavior of these two hybrid line. Present studies have shown that there were variations between the CMS and its maintainer lines whether on floral trait or flowering behavior for both hybrid rice combinations. The results showed that stigma characters for both 0025A and 0047 were superior than their respective maintainers. Therefore, it is expected that the out-crossing rate would be high. Seeding date intervals need to be done on 0025A/0025B during nursery stage because the on-set of flowering between parental lines was significantly different. Panicle of both CMS was also classified as just exserted and partially-exserted and application of exogenous hormones such as gibberellic acid was useful to improve panicle elongation and consequently increase the seed set and yield. Correlation study indicates that the stigma area of both 0025A and 0047A has significant positive correlation with out-crossing rate

A preliminary study on kenaf (Hibiscus cannabinus L.) accessions for fibre and pulp production (Kajian awal aksesi kenaf (Hibiscus cannabinus L.) untuk penghasilan serabut dan pulpa)

Abstrak Kenaf (Hibiscus cannabinus L.) merupakan pokok semusim daripada famili Malvaceae yang digunakan sebagai bahan asas dalam penghasilan tali, karung, kanvas dan permaidani. Sejumlah 16 aksesi kenaf telah dikaji dari segi pertumbuhan termasuklah bentuk daun, pigmentasi batang, saiz biji benih (mengikut isipadu) dan fenologi bagi setiap aksesi. Bentuk daun terbahagi kepada jejari atau bulat. Pigmentasi batang pula adalah hijau muda, hijau gelap atau hijau kemerahan dan ini boleh dibezakan antara aksesi. Abstract Kenaf (Hibiscus cannabinus L.), a herbaceous annual plant of the Malvaceae family, is one of the important source of raw materials for the traditional production of rope, sack, canvas and carpet. A total of 16 accessions were evaluated for growth performance including leaf shape, stem pigmentation, seed size (by volume) and the phenology of each accession. Leaf shape can be classified as palmate or cordate. Stem pigmentation is either light green, dark green or reddish green and it can be distinguished among all accessions. The tallest accessions were MK 13, MK 12, MK 23 and MK 22, while MK 19, MK 13, MK 04 and MK 28 showed the largest basal stem diameter. Accessions that gave high fibre and pulp yields such as MK 04, MK 12, MK 13, MK 19, MK 21, MK 22, MK 23, MK 25 and MK 28 were chosen for further testing on fibre and pulp production at multilocations

Grain quality performance and heritability estimation in selected F1 rice genotypes

A total of 17 rice genotypes consisted of 12 F1 progenies and five parental lines were evaluated for performance of grain qualities, yield and yield components and vegetative traits at the Malaysian Agricultural Research and Development Institute (MARDI) Research Station in Seberang Perai, Penang. Except grain length, all other grain quality characters, yield components and vegetative traits varied significantly among the genotypes. Among the studied characters, the highest heritability value was observed in plant height with 99.75% followed by panicle length having 96.90% and grain shape with 56.70% which could be successfully inherited to the next generations. The rest of the traits had low heritability values and ranged from 20.24 to 35.88%. This indicates that the characters are mainly influenced by environmental factors such as geographical effects and climate. However, in the quantitative traits such as grain qualities and yield components, they are usually difficult to inherit to the next generation due to low heritability values. The combinations of Q76 and MR84 had the highest in amylose content while Q76 and MRQ74 had the lowest. Several selected F1 indica rice genotypes from this evaluation are useful for future breeding programme and biotechnological research for the improvement of valuable grain quality traits

Development of advanced fragrant rice lines from MR269 × Basmati 370 through marker-assisted backcrossing

Fragrance in rice is an appealing attribute to consumers. The increasing demand for fragrant rice highlights the need to develop fragrant rice variety that suit the preference of local consumers in addition to reduce fragrant rice imports. Marker-assisted backcrossing (MABC) was employed to develop advanced fragrant rice lines from the cross between MR269 and Basmati 370. MR269 is a Malaysian high-yielding rice variety but non-fragrant and was used as recurrent parent whereas Basmati 370 is a well-known fragrant traditional rice variety and was used as donor parent for the fragrance gene. Two generations of backcrosses and a generation of selfing were conducted to introgress the fragrance gene and restore the recurrent parent genome in the backcross progenies. As a result, 14 advanced fragrant rice lines were developed. These advanced fragrant rice lines carried homozygous alleles for the fragrance gene, similar to Basmati 370. The average recovery of recurrent parent genome was 88.4%. Besides being fragrant, the advanced fragrant rice lines also had most of the morphological and agronomical traits similar to MR269. Grain quality of the advanced fragrant rice lines in terms of gelatinization temperature, amylose content and gel consistency are also similar to both parents. Besides, the advanced fragrant rice lines had 2-acetyl-1-pyrroline content similar to Basmati 370. MABC approach applied in this study has successfully introgressed the fragrance gene and accelerated the recovery of recurrent parent genome in advanced fragrant rice lines, therefore these lines can be delivered to the farmers and consumers for use in due time

Genotype × Environment interaction and stability analyses of yield and yield components of established and mutant rice genotypes tested in multiple locations in Malaysia

Genotypes evaluation for stability and high yielding in rice is an important factor for sustainable rice production and food security. These evaluations are essential especially when the objective of the breeding program is to select lines with high adaptability and stability. This study was conducted to investigate G × E interaction over ten environments across the peninsular Malaysia for yield stability in fifteen rice genotypes comprising twelve mutant lines and three established varieties. The experiment was laid out in a randomized complete block design with three replications across the environments. Yield component traits were evaluated over multiple harvests and measured as number of tillers per hill, filled grains per panicle, grain weight per hill and yield per hectare. Data analyses were through analyses of variance and stability analyses were conducted for univariate and multivariate stability parameters. The pooled analysis of variance showed highly significant differences among genotypes, locations, seasons, and genotypes by environment (G × E interaction) for all the traits. Based on univariate (bi, , σi2, Wi2, YSi) and multivariate (AMMI and GGE biplot) stability parameters, rice genotypes were classified into three main groups. The first group are genotypes having high stability along with high yield. These genotypes are widely adapted to diverse environmental conditions. The second group is a genotype that exhibited high yield but low stability, this genotype is suitable for specific environments. The last group is genotypes with low yield and high stability. Genotypes in this class are more suitable for breeding specific traits or yield component compensation such as the capacity to recover rapidly from stresses. Significant rank correlations were measured for regression slope (bi), deviation from regression (), Shukla stability variance (), Wricke’s ecovalence (), and Kang stability statistic (YSi) for all the traits

Biochemical, genetic and molecular advances of fragrance characteristics in rice

One of the most valuable traits in high-quality rice is aroma or fragrance, which is important for consumer preference and global trade. Aromatic rice is unique and recognized as a badge of honor and an asset in many countries. Among more than 100 volatile components, 2-acetyl-1-pyrroline (2AP) is believed to be the main aromatic compound in rice. The principal gene contributing to 2AP is badh2, which was mapped on chromosome 8 by map-based cloning. A deletion in this gene truncates and makes non-functional the BADH2 protein. Thus, the mutant badh2 transcript leads to 2AP accumulation in aromatic rice. The discovery of the gene has led to the clarification of the biochemistry, molecular genetics and evolution of fragrant rice. The breeding of fragrant rice is now faster because of marker assisted selection (MAS), which is based on recognized genes. For a more extensive elucidation of all effective and fundamental factors contributing to rice fragrance, it is essential to further explore target quantitative trait loci (QTLs) and their inheritance and locations

Physicochemical characteristics and nutritional compositions of MR219 mutant rice and their effects on glycaemic responses in BALB/c mice

The awareness of the general public on healthy foods has been a major concern and people are looking for the right variety of rice for diabetic patients. High amylose content rice with low glycaemic index (GI), which is an indicator of sugar release in the blood, is beneficial for human health. The present work was aimed to determine the physicochemical characteristics and nutritional compositions of MR219 mutant rice, and the effects of amylose content to blood glucose response and glycaemic index in field condition. A total of 31 M4 mutant lines (ML1 to ML31) were evaluated for physicochemical characteristics and nutritional compositions in comparison with the parental variety, MR219. In glycaemic response study, 48 female BALB/c mice were fed with glucose (a baseline), saline water, two check varieties (MR219 and MRQ74) and four selected mutant lines with different amylose contents. The physicochemical and proximate analysis revealed highly significant differences among the mutant lines. Some mutant lines improved amylose content and nutritional composition. Mutant ML3 had slightly higher amylose content than the parental variety and was recommended for glycaemic responses. However, the field experiment results showed two mutant lines namely; ML3 and ML30, having significantly lower glucose reading (5.49 mmol/L and 5.47 mmol/L, respectively) as compared to the parental variety and other mutant lines. The glucose level was found highest at 60 min after feeding but significantly dropped at 120 min. The normal glucose reading in ML3 and ML30 also resulted in moderate GI values (65% and 66%, respectively). As low and moderate GI foods are recommended for diabetic patients, ML3 and ML30 had high potential for their consumption, and can be suggested for further breeding program to develop low GI rice

A review on gene pyramiding of agronomic, biotic and abiotic traits in rice variety development

Rice Oryza sativa L is a staple food crop, and its seeds are the most important component part of the agronomic trait of the cereal crop, rich in nutrient and of economic value to human and even livestock. But, it is often threatened by various abiotic and biotic conditions that reduce the yield, because of high incidences of infectious disease agents and non-pathogenic conditions respectively. Pyramiding of the requisite resistance and tolerance genes into single elite high yielding variety of rice, confers wider spectrum of stress management, resulting to development of single multiline variety of rice. Marker-assisted selection utilizes DNA marker-linked primers for blast resistant gene (RM8225;Piz, RM6836;Piz, Pi2,Pi9), bacteria leaf blight (RM224; Xa-4, RM122;xa-5, RG136; xa-13, RM21;Xa-21) and drought tolerance (RM236;qDTY2.2, RM520;qDTY3.1, RM511;qDTY12.1) in pedigree, backcross and recurrent selection breeding methods. The objectives are to create awareness on the environmental safety of host-resistance, significance of single multiline resistance variety, effect of the interaction of stress conditions and associated simple sequence repeat (SSR) linked markers

Blast resistance in rice: a review of conventional breeding to molecular approaches

Blast disease caused by the fungal pathogen Magnaporthe oryzae is the most severe diseases of rice. Using classical plant breeding techniques, breeders have developed a number of blast resistant cultivars adapted to different rice growing regions worldwide. However, the rice industry remains threatened by blast disease due to the instability of blast fungus. Recent advances in rice genomics provide additional tools for plant breeders to improve rice production systems that would be environmentally friendly. This article outlines the application of conventional breeding, tissue culture and DNA-based markers that are used for accelerating the development of blast resistant rice cultivars. The best way for controlling the disease is to incorporate both qualitative and quantitative genes in resistant variety. Through conventional and molecular breeding many blast-resistant varieties have been developed. Conventional breeding for disease resistance is tedious, time consuming and mostly dependent on environment as compare to molecular breeding particularly marker assisted selection, which is easier, highly efficient and precise. For effective management of blast disease, breeding work should be focused on utilizing the broad spectrum of resistance genes and pyramiding genes and quantitative trait loci. Marker assisted selection provides potential solution to some of the problems that conventional breeding cannot resolve. In recent years, blast resistant genes have introgressed into Luhui 17, G46B, Zhenshan 97B, Jin 23B, CO39, IR50, Pusa1602 and Pusa1603 lines through marker assisted selection. Introduction of exotic genes for resistance induced the occurrence of new races of blast fungus, therefore breeding work should be concentrated in local resistance genes. This review focuses on the conventional breeding to the latest molecular progress in blast disease resistance in rice. This update information will be helpful guidance for rice breeders to develop durable blast resistant rice variety through marker assisted selection