Assam Type Research Articles

Fusing Architecture as a Catalyst for Reviving the Cultural Values of Assam

This paper explores the diverse cultural tapestry of Assam and its role in fostering a sense of belonging and connecting individuals with nature and society. It intends to infer attributes of bygone Assam type houses and find ways to integrate them in contemporary prevalent construction techniques. By comprehensively analyzing Assam's cultural heritage, the paper emphasizes the ongoing need to nurture and protect cultural diversity. It highlights the significance of cultural exchange, dialogue, and mutual respect in this endeavor. Recognizing the intricate relationship between culture, society, and the environment, the study promotes a profound appreciation for Assam's unique heritage while paving the way for sustainable development and harmonious coexistence in a world that is constantly evolving.

A highly efficient protocol for isolation of protoplast from China, Assam and Cambod types of tea plants [Camellia sinensis (L.) O. Kuntze

BackgroundTea is the most popular beverage worldwide second only to water. Its demand is tremendously rising due to increased awareness of its medicinal importance. The quality and uses of tea depend on the tea-types which are mainly three types including China, Assam and Cambod type having distinct compositions of secondary metabolites. Huge variation in secondary metabolites in different tea-types and cultivars limited the successful application of various approaches used for its trait improvement. The efficiency of a protocol for isolation of protoplast is specific to the types and cultivars of tea plants. The existing tea protoplast-isolation protocols [which were optimized for tea-types (China and Assam type) and Chinese cultivars grown in China] were found ineffective on types/cultivars grown in India due to type/cultivar variability. Therefore, optimization of protoplast-isolation protocol is essential for tea-types/cultivars grown in India, as it is the second largest producer of tea and the largest producer of black tea. Here, efforts were made to develop an efficient protoplast-isolation protocol from all major types of tea (China, Assam and Cambod types) grown in India and also from three types of tender leaves obtained from field-grown, hydroponically-grown and tissue culture-grown tea plants.ResultsDeveloped protoplast-isolation protocol was effective for different types of leaf tissue obtained from the tender leaves of field-grown, hydroponically-grown and tissue culture-grown tea plants. Moreover, optimized protocol effectively worked on all three types of tea including China, Assam and Cambod types cultivated in India. The digestion of leaves with 3% cellulase R-10, 0.6% macerozyme, 1% hemicellulase and 4% polyvinylpyrrolidone for 12 h at 28ºC yielded approximately 3.8–4.6 × 107 protoplasts per gram fresh tissue and 80–95% viability in selected tea cultivars, and tissue culture plant material was found most appropriate for protoplast isolation.ConclusionsIn conclusion, we reported an efficient protocol for isolation of protoplasts from tender tea leaves of all major tea-types (China, Assam and Cambod) grown in India. Moreover, the protocol is also effective for tender-leaf tissue of field-grown, hydroponically-grown and tissue culture-grown tea plants. The findings are expected to contribute to the genetic improvement of tea traits widely.

Development of SNP Markers for Original Analysis and Germplasm Identification in Camellia sinensis.

Tea plants are widely grown all over the world because they are an important economic crop. The purity and authenticity of tea varieties are frequent problems in the conservation and promotion of germplasm resources in recent years, which has brought considerable inconvenience and uncertainty to the selection of parental lines for breeding and the research and cultivation of superior varieties. However, the development of core SNP markers can quickly and accurately identify the germplasm, which plays an important role in germplasm identification and the genetic relationship analysis of tea plants. In this study, based on 179,970 SNP loci from the whole genome of the tea plant, all of 142 cultivars were clearly divided into three groups: Assam type (CSA), Chinese type (CSS), and transitional type. Most CSA cultivars are from Yunnan Province, which confirms that Yunnan Province is the primary center of CSA origin and domestication. Most CSS cultivars are distributed in east China; therefore, we deduced that east China (mainly Zhejiang and Fujian provinces) is most likely the area of origin and domestication of CSS. Moreover, 45 core markers were screened using strict criteria to 179,970 SNP loci, and we analyzed 117 well-Known tea cultivars in China with 45 core SNP markers. The results were as follows: (1) In total, 117 tea cultivars were distinguished by eight markers, which were selected to construct the DNA fingerprint, and the remaining markers were used as standby markers for germplasm identification. (2) Ten pairs of parent and offspring relationships were confirmed or identified, and among them, seven pairs were well-established pedigree relationships; the other three pairs were newly identified. In this study, the east of China (mainly Zhejiang and Fujian provinces) is most likely the area of origin and domestication of CSS. The 45 core SNP markers were developed, which provide a scientific basis at the molecular level to identify the superior tea germplasm, undertake genetic relationship analysis, and benefit subsequent breeding work.

Transcriptional Comparison of New Hybrid Progenies and Clone-Cultivars of Tea (Camellia sinensis L.) Associated to Catechins Content.

Heterosis or hybrid vigor is the improved performance of a desirable quality in hybrid progeny. Hybridization between high-productive Assam type and high-quality Chinese type clone-cultivar is expected to develop elite tea plant progenies with high quality and productivity. Comparative transcriptomics analyses of leaves from the F1 hybrids and their parental clone-cultivars were conducted to explore molecular mechanisms related to catechin content using a high-throughput next-generation RNA-seq strategy and high-performance liquid chromatography (HPLC). The content of EGCG (epigallocatechin gallate) and C (catechin) was higher in ‘Kiara-8’ × ‘Sukoi’, ‘Tambi-2’ × ‘Suka Ati’, and ‘Tambi-2’ × ‘TRI-2025’ than the other hybrid and clone-cultivars. KEGG (Kyoto Encyclopedia of Genes and Genomes) and GO (Gene Ontology) analysis found that most pathways associated with catechins content were enriched. Significant differentially expressed genes (DEGs) mainly associated with phenylpropanoid, flavonoid, drug metabolism-cytochrome P450, and transcription factor (MYB, bHLH, LOB, and C2H2) pathways appeared to be responsible for the high accumulation of secondary metabolites in ‘Kiara-8’ × ‘Sukoi’, ‘Tambi-2’ × ‘Suka Ati’, and ‘Tambi-2’ × ‘TRI-2025’ as were detected in EGCG and catechin content. Several structural genes related to the above pathways have been obtained, which will be used as candidate genes in the screening of breeding materials.

Energy absorption behavior of bamboo concrete composite wall panel

The use of renewable, natural building materials like bamboo for wall construction has a great advantage over conventional non-green walling materials. The woven bamboo striped cement mortar plastered walling system or Bamcrete panel technology has a great prospect with its eco-friendly nature. For a long time, this has been traditionally adopted in north-eastern regions of India in the construction of ‘Assam type house’. But this wall technology is not been exposed in modern-day construction. It is important to emphasize this technology, hence this research study presents an experimental study of energy absorption characteristics of Bamcrete panel under the impact and monotonic loading conditions to highlight the possible improvement of the traditional Ekra wall of Assam type house based on different parametric variations in the fabrication of panels like framing options, type of bamboo species, panel weaving technique, and panel casting using different design mix mortar at different strengths were studied. The standard BS: 5234–2:1992 [1] was followed to carry out the small hard body impact test and static load test in the constructed Bamcrete partition panels. The variation of bamboo species does not affect significantly in the energy absorption capacity of Bamcrete panels and the impact resistance of panels increased significantly using design mix mortar compared to the traditional mason mix mortar.

Study of bamcrete wall panel in the traditional Assam Type house

Bamboo is a commonly used wall material for ages. Bamboo mesh with mud plaster popularly known as Ekra wall (or as Shamig in Bhutan) is a kind of wattle and daub walling system is very popular. This mud plaster was replaced with cement mortar and became very common in the north-eastern part of India and is known as Assam type house. This modified walling system is called Bamcrete wall in this paper. This sustainable technology is rapidly losing its popularity due to the lack of scientific studies and the ingression of modern multi-storied building concepts. Presently, the wall construction consumes a huge quantity of non-renewable resources, but this Bamcrete walling system provides a good alternative by consuming the natural renewable resource bamboo. This paper presents, the strength and durability study of a 40-years old Bamcrete walled Assam type house. The panel strength was tested based on a hard-body horizontal impact test. The energy absorption behavior of the traditional mason mortar plaster of Bamcrete wall construction was compared with lab-cast Bamcrete panels. The panel was cast using design mix mortar showed significant improvement in their impact resistance. It was observed that even after 40-years of construction, bamboo remains well intact inside the mortar plaster without any deterioration.

Niche differentiation of belowground microorganisms and their functional signatures in Assam type tea (Camellia sinensis var. assamica).

We employed an Illumina-based high-throughput metagenomics sequencing approach to unveil the rhizosphere and root endosphere microbial community associated with an organically grown Camellia population located at the Experimental Garden for Plantation Crops, Assam (India). The de novo assembled tea root endosphere metagenome contained 24,231 contigs (total 7,771,089 base pairs with an average length of 321 bps), while tea rhizosphere soil metagenome contained 261,965 sequences (total 230,537,174 base pairs, average length 846). The most prominent rhizobacteria belonged to the genera, viz., Bacillus (10.35%), Candidatus Solibacter (6.36%), Burkholderia (5.19%), Pseudomonas (3.9%), Streptomyces (3.52%), and Bradyrhizobium (2.77%), while the root endosphere was dominated by bacterial genera, viz., Serratia (46.64%), Methylobacterium (8.02%), Yersinia (5.97%), Burkholderia (2.05%), etc. The presence of few agronomically important bacterial genera, Bradyrhizobium, Rhizobium (each 0.93%), Sinorhizobium (0.34%), Azorhizobium, and Flavobacterium (0.17% each), was also detected in the root endosphere. KEGG pathway mapping indicated the presence of microbial metabolic pathway genes related to tyrosine metabolism, tryptophan metabolism, glyoxylate, and dicarboxylate metabolism which play important roles in endosphere activities, including survival, growth promotion, and host adaptation. The root endosphere microbiome also contained few important plant growth promoting traits related to phytohormone production, abiotic stress alleviation, mineral solubilization, and plant disease suppression.

Recurrent secondary embryogenesis in androgenic embryos and clonal fidelity assessment of haploid plants of Tea, Camellia assamica ssp. assamica and Camellia assamica ssp. lasiocaylx

Globular androgenic haploid embryos of TV21 and TV19 cultivars of Camellia ssp., obtained on embryo induction medium (EIM), Murashige and Skoog medium with 10 µM 6-benzylaminopurine (BAP), 3 µM gibberellic acid (GA3), 800 mg l−1 L-glutamine and 200 mg l−1 L-serine, were pretreated with 18 µM abscisic acid (ABA) and 25 g l−1 mannitol for 20 days in liquid medium to attain maturation. The pre-treatment favoured the primary globular embryos to grow and pass through all the developmental stages from globular, heart-shape, torpedo shape to fully matured docotyledonous embryos. Fivefold and threefold increase in secondary embryogenesis (SE) was attained in Camellia assamica ssp. assamica (TV21; Assam Type) and Camellia assamica ssp. lasiocaylx (TV19; Cambod Type), respectively, when pre-treated primary embryos were transferred to the liquid embryo development (ED) medium, supplemented with tenfold reduced concentration of growth regulators that were present in EIM. Embryos were germinated well on 10 µM BAP, 0.5 µM GA3, 1 µM indole-3-butyric acid (IBA), 80 mg l−1 L-glutamine and 20 mgl−1 L-serine, following liquid-to-semi-solid transition method. Well developed shoots and roots were formed when embryos were initially kept for four weeks in liquid germination medium, followed by their transfer to semi-solid medium on similar medium composition. The method promoted recurrent secondary embryogenesis in lesser time with highest germination rate, 66.6% and 30.3% in TV21 and TV19 cultivars, respectively. Histology and field emission scanning electron microscopy (FESEM) were performed to determine ontological events during embryo development. Clonal fidelity of haploid plantlets was assessed using random amplified polymorphic DNA (RAPD) to ensure no somaclonal variations occurred during the multistep process of secondary embryogenesis, embryo maturation and germination. A two-step transition protocol from liquid-semi-solid medium is beneficial for embryos to overcome hyperhydricity. Secondary embryogenesis is the best mode to obtain genetically uniform true-to-type haploid plantlets.

Comparative analysis of chloroplast genomes indicated different origin for Indian tea (Camellia assamica cv TV1) as compared to Chinese tea

Based upon the morphological characteristics, tea is classified botanically into 2 main types i.e. Assam and China, which are morphologically very distinct. Further, they are so easily pollinated among themselves, that a third category, Cambod type is also described. Although the general consensus of origin of tea is India, Burma and China adjoining area, yet specific origin of China and Assam type tea are not yet clear. Thus, we made an attempt to understand the origin of Indian tea through the comparative analysis of different chloroplast (cp) genomes under the Camellia genus by performing evolutionary study and comparing simple sequence repeats (SSRs) and codon usage distribution patterns among them. The Cp genome based phylogenetic analysis indicated that Indian Tea, TV1 formed a different group from that of China tea, indicating that TV1 might have undergone different domestications and hence owe different origins. The simple sequence repeats (SSRs) analysis and codon usage distribution patterns also supported the clustering order in the cp genome based phylogenetic tree.

The Chromosome-Level Reference Genome of Tea Tree Unveils Recent Bursts of Non-autonomous LTR Retrotransposons in Driving Genome Size Evolution

The Chromosome-Level Reference Genome of Tea Tree Unveils Recent Bursts of Non-autonomous LTR Retrotransposons in Driving Genome Size Evolution

Measurement of natural radioactivity of building materials used in the southern valley region of Manipur, India

A study of natural radionuclides of different types of houses was conducted at 493 houses in the southern valley region of Manipur, India. The average annual effective doses of gamma radiation level in indoor and outdoor were estimated from the measurements using Micro R-survey meter and found as 1.25 ± 0.10 (range: 1.02–1.38) mSv/y and 0.76 ± 0.08 (range: 0.58–0.99) mSv/y for reinforced cement concrete (RCC) houses, followed by 1.07 ± 0.09 (range: 0.95–1.19) mSv/y and 0.76 ± 0.08 (range: 0.67–0.95) mSv/y for Adobe laid earthen houses, 1.05 ± 0.09 (range: 0.78–1.24) mSv/y and 0.74 ± 0.08 (range: 0.58–0.91) mSv/y for Assam-type (AT) brick houses, 0.83 ± 0.09 (range: 0.40–1.07) mSv/y and 0.72 ± 0.08 (range: 0.23–0.97) mSv/y for AT mud houses and 0.73 ± 0.08 (range: 0.66–0.82) mSv/y and 0.74 ± 0.07 (range: 0.64–0.82) mSv/y for AT katcha houses. The activity concentration226Ra,232Th, and40K of building materials was evaluated using the gamma ray spectrometry and found average value as 42.4 (range: 23.0–69.9) Bq/kg, 111.3 (range: 23.8–214.5) Bq/kg, and 1369.0 (range: 995.7–2284.6) Bq/kg. Moreover, the annual effective dose conceived from the building material was found as 1.1 mSv/y from Portland cement, 1.4 mSv/y from sand, and 1.5 mSv/y from brick. Seasonal variations of indoor effective dose rates were observed in RCC houses; the highest dose rate was observed during the premonsoon season followed by postmonsoon and least with monsoon season.

Behavior of bamboo wall panel under bullet impact load

Bamboo mesh plastered with mud was a popular walling material across the world. About 100 years ago, this system was modified by applying mortar in place of mud, revising the Ekra wall system. The houses usually have wooden battens with bamboo mesh plastered with mortar usually called an Assam type house. This technology has become common in the north-eastern part of India and now it is rapidly going towards extinction in modern-day construction. This paper presents the efforts to find out the energy absorption by Bamcrete wall panels compared to the RCC panel under bullet impact load. Three different types of panels i.e. single, twin mesh Bamcrete and RCC panel were constructed. Two types of bullet SLR 7.62 mm and INSAS 5.56 mm were used in this study. The study showed that the twin mesh Bamcrete panel absorb higher energy as compared to RCC panel.

Recent progress of intra-specific hybridization of tea (<em>Camellia sinensis,</em> (L.) O. Kuntze) in Sri Lanka

Tea germplasm accessions are the most valuable material for tea breeding. However its utilization in the past was limited due to lack of available information. Recently generated information on genetic structure and metabolite profiles of the germplasm were used in selecting parents for hybridization programmes from 2012 to 2016. The main focus of the programme was to make crosses between three taxa of tea viz. Camellia. sinensis var. assamica (Assam type), C. sinensis var. sinensis (China type) and C. sinensis spp. lasiocalyx (Cambod type). Pollinated buds were closely-monitored and the number of crosses, number of fruits, number of seeds and reproductive parameters were recorded. A total of 3978 crosses (2405 direct crosses and 1573 reciprocal crosses) were made and 974 seeds were obtained from 595 fruits. Percentages of fruit set and seed set varied significantly among different families. Irrespective of the inter-subspecies groups, the percentage of seed germination was above 50% and was not significantly-different. Cross compatibility between taxa in terms of percentage of fruit set ranged from 4.6% to 25.6% and varied significantly. Among the inter-subspecies crosses the Assam varieties were found to be the best as female parent. The generated information would be useful for selection of parents and tea improvement programmes in the future.

Understanding the genetic relationships and breeding patterns of Sri Lankan tea cultivars with genomic and EST-SSR markers

Sri Lanka is the second largest global tea exporter. Genetically diverse planting material are vital in adjusting for biotic and abiotic stresses. Accordingly, sixty four tea cultivars, which represent the entirety of the recommended cultivars consisting of 50 improved cultivars and 14 Estate selections were analyzed at 33 Genomic and EST-SSR loci with the objective of assessing the genetic diversity and population structure of cultivated tea in Sri Lanka. Genotypic data were subjected to cluster and population structure analysis using power marker and Structure software. The results revealed three groups in the dendrogram and the population structure was described at the level of three sub-populations; the main sub-populations deriving from a single Assam type tea plant and the other two from old seedling teas and the hybrids between the above sub-populations. The cultivated tea in Sri Lanka were thus revealed to be of vary narrow genetic base dominated by the Assam type tea of Indo-Chinese origin. In conclusion, it is urged for enhancing the genetic diversity of the cultivated tea by incorporating exotic China type tea germplasm and more parents from old seedling teas grown in Sri Lanka in the breeding programme.

Seasonal Variations in Catechins and Caffeine Profiles among Tea Cultivars Grown in Kenya

Consumption of beverage tea rich in flavonoids is associated with a wide range of health benefits. However, the industry in Kenya has over-relied on black tea whose sustainability is not guaranteed due to glut in the market resulting in low income to farmers. Product characteristics and prices are determined based on the accumulation of the phenolic compounds that are profoundly influenced by environmental and cultivar differences. Profiles of quality-related components were assessed in six new and existing cultivars over three distinct annual seasons. Weather data indicated the wet-cold (April–August) season received the largest amount of precipitation and highest relative humidity, while the hot-dry season (January to March) was the driest with a lower relative humidity. Total catechin (TC) contents were significantly (P less than or equal to0.05) different among the cultivars, seasons, and interactions season x site and cultivar x season x site. Overall, the purple-leafed cultivars had lower TC content compared to the green-leafed teas, whereas teas obtained during the WW season (September–December) had higher levels (14.3%) that are suitable for processing of high-quality tea products. Esterified catechins, EGCG and ECG, formed the major component among individual catechins studied. EGCG was significantly higher during both the CW and WW seasons. Cultivars of ‘China type’ accumulated higher +C content as compared to the ‘Assam type’. EC was highest during the WW season in Timbilil, while in Kangaita, the CW season had slightly higher content. Generally, the Cambod type cv. TRFK 301/1 had the highest caffeine content, while China type cv. TRFK 73/1 had the lowest content. Unlike catechin, caffeine content was highest during the HD season. This information is crucial for interventions on product diversification, value addition and novel marketing strategies in tea.

Domestication Origin and Breeding History of the Tea Plant (Camellia sinensis) in China and India Based on Nuclear Microsatellites and cpDNA Sequence Data.

Although China and India are the two largest tea-producing countries, the domestication origin and breeding history of the tea plant in these two countries remain unclear. Our previous study suggested that the tea plant includes three distinct lineages (China type tea, Chinese Assam type tea and Indian Assam type tea), which were independently domesticated in China and India, respectively. To determine the origin and historical timeline of tea domestication in these two countries we used a combination of 23 nSSRs (402 samples) and three cpDNA regions (101 samples) to genotype domesticated tea plants and its wild relative. Based on a combination of demographic modeling, NewHybrids and Neighbour joining tree analyses, three independent domestication centers were found. In addition, two origins of Chinese Assam type tea were detected: Southern and Western Yunnan of China. Results from demographic modeling suggested that China type tea and Assam type tea first diverged 22,000 year ago during the last glacial maximum and subsequently split into the Chinese Assam type tea and Indian Assam type tea lineages 2770 year ago, corresponding well with the early record of tea usage in Yunnan, China. Furthermore, we found that the three tea types underwent different breeding histories where hybridization appears to have been the most important approach for tea cultivar breeding and improvements: a high proportion of the hybrid lineages were found to be F2 and BCs. Collectively, our results underscore the necessity for the conservation of Chinese Assam type tea germplasm and landraces as a valuable resource for future tea breeding.

Indications for Three Independent Domestication Events for the Tea Plant (Camellia sinensis (L.) O. Kuntze) and New Insights into the Origin of Tea Germplasm in China and India Revealed by Nuclear Microsatellites.

BackgroundTea is the world’s most popular non-alcoholic beverage. China and India are known to be the largest tea producing countries and recognized as the centers for the domestication of the tea plant (Camellia sinensis (L.) O. Kuntze). However, molecular studies on the origin, domestication and relationships of the main teas, China type, Assam type and Cambod type are lacking.Methodology/Principal FindingsTwenty-three nuclear microsatellite markers were used to investigate the genetic diversity, relatedness, and domestication history of cultivated tea in both China and India. Based on a total of 392 samples, high levels of genetic diversity were observed for all tea types in both countries. The cultivars clustered into three distinct genetic groups (i.e. China tea, Chinese Assam tea and Indian Assam tea) based on STRUCTURE, PCoA and UPGMA analyses with significant pairwise genetic differentiation, corresponding well with their geographical distribution. A high proportion (30%) of the studied tea samples were shown to possess genetic admixtures of different tea types suggesting a hybrid origin for these samples, including the Cambod type.ConclusionsWe demonstrate that Chinese Assam tea is a distinct genetic lineage from Indian Assam tea, and that China tea sampled from India was likely introduced from China directly. Our results further indicate that China type tea, Chinese Assam type tea and Indian Assam type tea are likely the result of three independent domestication events from three separate regions across China and India. Our findings have important implications for the conservation of genetic stocks, as well as future breeding programs.

English

Six iBPS primers and twenty-one morphological traits were used to assess the genetic diversity and relationships of 15 tea [Camellia sinensis (L.) O. Kuntze] accessions grown in Vietnam. The similarity index matrix generated from Dice coefficient (iPBS analysis) and the dissimilarity index matrix generated from Euclidian distance coefficient (morphological analysis) were used to build the respective un-weighted pair group method with arithmetic average (UPGMA) derived-dendrograms revealing the genetic relationships among the tested tea accessions. The iPBS analysis showed a slightly different result as compared to the result of morphological analysis which indicated that the group of Shan and Assam type were separate from the group of China type and the hybrids related to China type. Meanwhile, the iPBS analysis clustered 15 tea genotypes into two main groups; the tea genotypes of small leaved China, Assam-small leaved China hybrid and Shan-large leaved China hybrid type, with small leaf size, came together into one group; the other one was mainly nested by the tea genotypes of Shan, Assam and Shan-small leaved China type, with large leaf size. However, the iPBS analysis also shared the same basic agreements with the morphological analysis. All the tea genotypes, which originated from the same parents or the same type of crossing parental couple, revealed close relatedness. The results of morphological analysis are conformable with the conventional classification of tea taxa and give basic relative information among 15 tea genotypes to demonstrate particularly the result of molecular analysis. It could be concluded that iPBS is a useful DNA based-marker for evaluation of genetic diversity and relationships of tea. © 2016 Friends Science Publishers

English

Tea has long been a well-known crop for its economic value and widening the genetic variability of tea family is often necessitated. Hybridization programs at intraspecific level have been greatly fascinated as potential and useful methods in tea plant breeding to widening the genetic diversity. This comparative study was intended to explore a new avenue to develop the tea plant breeding programs through evaluating remote intraspecific cross-compatibility between Camellia sinensis var. sinensis (L.) O. Kuntze and C. sinensis var. assamica (Masters). Remote intraspecific cross-compatibility was assessed by comparing and contrasting the in-vivo pollen germination and pollen tube growth using fluorescence microscopy and the subsequent fruit set following controlled self- and cross-pollinations. In-vivo pollen germination and pollen tube growth was examined at 1 day, 3 days, and 14 days after pollination treatments, but disparity was not observed in pollen germination and pollen tube growth between self- and cross-pollinations. Early fruit set was evaluated at 3 months and 6 months after pollination. Fruit set was observed in cross-pollination except self-pollination. A late-acting self-incompatibility system or post-zygotic barriers and close intraspecific cross-compatibility were confirmed within C. sinensis var. sinensis (L.) O. Kuntze. Potential remote intraspecific cross-compatibility was recorded from cultivars crossed between China type and Assam type tea. The present findings bestow the significant contribution to develop the future tea breeding programs. Key words: Intraspecific cross, pollen germination, pollen quality, pollination, tea breeding.

Construction of a genetic linkage map and mapping of drought tolerance trait in Indian beveragial tea

Tea is an important health drink which contributes significantly to the economy of Asian and African countries. India contributes about 29 % of the world’s total tea production where majority of the tea cultivated is Assam type (native to Assam, India). Apart from India, Assam type contributes to the majority of tea grown in tropical regions of Sri Lanka and Kenya as well. We have developed the first genetic linkage map in Indian beveragial tea using 234 DNA markers (AFLP and RAPD). The plausibility of the linkage group formation was compared using two-way pseudo-testcross approach (using maximum likelihood algorithm) and integrated approaches (using regression algorithm). Both the approaches generated linkage maps containing 18 linkage groups. The composition and order of markers in the corresponding linkage groups in both the maps showed significant congruence. Maximum likelihood algorithm could map 78.6 % of the markers with total map length of 8527.5 and 45.3 cM average distance between each marker. Regression algorithm could map 73.5 % of the total markers with total map length of 2051.7 and 14.96 cM average distance between each marker. Drought is the major abiotic stress responsible for heavy yield losses in cultivated tea all over the world. The present map was used to map the locus, AFLP_CS_87 that segregates with drought tolerance phenotype in both the maps.