DSpace Repository :: Browsing by Author "Jerard, B.A."

Browsing by Author "Jerard, B.A."

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Application of RAPD markers in hybrid verification in coconut
(2014) Rajesh, M.K.; Jerard, B.A.; Preethi, P.; Regi Jacob Thomas; Anitha Karun
Coconut palms are classified into two major types, viz., ‘talls’ and ‘dwarfs’, which mainly differ in their pollination behavior of cross- and self-pollination, respectively. Due to this difference, getting true-to-type progenies of desirable tall and dwarf cultivars has always been a challenge. The conventional practice of selection of seedlings based solely on morphological traits often results in selection of out-crossed seedlings and undesirable off-types. In the present investigation, RAPD markers for the tall/dwarf trait were identified in coconut using a bulked DNA approach. Screening of tall and dwarf palm bulk DNA with 200 primers revealed a RAPD primer OPBA3 which was able to clearly differentiate both the tall and dwarf bulks. For validation, the primer was used to screen individual tall and dwarf coconut palms representing different geographic regions. The primer was also used to screen the parents and validate hybrids of Dwarf x Tall crosses.
Authentication of coconut hybrids using RAPD analysis
(2012-11) Rajesh, M.K.; Preethi, P.; Jerard, B.A.; Regi Jacob Thomas; Anitha Karun
Botany, Growth and Development
(2017) Niral, V.; Jerard, B.A.
Breeding
(2017) Jerard, B.A.; Niral, V.; Chowdappa, P.
Characterization and diversity assessment in coconut collections of Pacific Ocean Islands and Nicobar Islands
(2012-12) Sankaran, M.; Damodaran, V.; Singh, D.R.; Jai Sankar, I.; Jerard, B.A.
Characterization and genetic diversity assessment among 30 conserved coconut accessions collected from Pacific Ocean Islands and Nicobar Islands for morphological traits, physico-chemical traits of tender nut water, leaf biochemical parameters and molecular characterization by using random amplified polymorphic DNA (RAPD) markers were undertaken at World Coconut Germplasm Centre, Andaman. Significant variations were observed for most morphological and nut component traits. Out of the 30 accessions characterized, four accessions, namely, Niu Leka, Hari Papua, Niu Oma and Nikkore were dwarfs among which Niu Leka was identified as a unique dwarf with higher copra content. A dendrogram of genetic relationship obtained through RAPD markers showed distinct variation with 66% in all accessions. The average polymorphic information content (PIC) value of 13 selected primers was 0.29 and maximum and minimum PIC values was 0.46 and 0.17 for primers OPF-19 and OPH-25, respectively. Cluster analysis by UPGMA method grouped the accessions into two major clusters. The results will be useful in the selection among these conserved accessions for specific traits for future utilization in crop improvement initiatives based on their performance for different desirable traits and the level of diversity.
Characterization of a spicata mutant of coconut palm in India
(Indian Society for Plantation Crops, 2014-04) Arunachalam, V.; Rajesh, M.K.; Jerard, B.A.; Jayabose, C.; Sairam, C.V.
Coconut (Cocos nucifera L.) Pollen Cryopreservation
(2014) Anitha Karun; Sajini, K.K.; Niral, V.; Amarnath, C.H.; Remya, P.; Rajesh, M.K.; Samsudeen, K.; Jerard, B.A.; Florent Engelmann
BACKGROUND: Coconut genetic resources are threatened by pests and pathogens, naturalhazards and human activities. Cryopreservation is the only method allowing the safe and costeffectivelong-term conservation of recalcitrant seed species such as coconut. OBJECTIVE: The objective of this work was to test the effect of cryopreservation and of cryostorage duration on coconut pollen germination and fertility. MATERIALS AND METHODS: Pollen of two coconut varieties (West Coast Tall WCT and Chowghat Orange Dwarf COD ) was collected in March-May over three successive years, desiccated to 7.5% moisture content (FW) and cryopreserved by direct immersion in liquid nitrogen. RESULTS: Germination and pollen tube length (PTL) of desiccated and cryopreserved pollen were not significantly different for both WCT and COD over the three harvest months of the three consecutive years of study. Pollen germination ranged from 24 to 32% in desiccated pollen whereas it was between 26 and 29% in cryopreserved COD pollen. In the case of WCT, germination ranged from 30 to 31% in desiccated pollen, while it was between 28 and 32% in cryopreserved pollen. PTL of cryopreserved pollen ranged between 224-390 m and 226-396 m for COD and WCT, respectively. Germination of COD pollen varied between 29.0 and 44.1% after 4 years and 1.0/1.5 years cryostorage, respectively. Germination of WCT pollen did not change significantly between 0 and 6 years cryostorage, being comprised between 32 (24 h) and 40 % (1.5 years). Germination and vigour of cryopreserved pollen were generally higher compared to that of pollen dried in oven and non-cryopreserved. Normal seed set was observed in COD and WCT palms using pollen cryostored for 6 months and 4 years. Cryopreserved pollen of five Tall and five Dwarf accessions displayed 24-31% and 25-49% germination, respectively. CONCLUSION: These results show that it is now possible to establish pollen cryobanks to contribute to coconut germplasm long-term conservation.
Combining ability in coconut (Cocos nucifera)
(2007-02-08) Nampoothiri, K.U.K.; Kumaran, P.M.; Jerard, B.A.; Ratnambal, M.J.; Rao, E.V.V.B.; Parthasarathy, V.A.
Conservation and utilization of soft endosperm coconut accession from Andaman Islands
(2013-04) Jerard, B.A.; Damodaran, V.; Niral, V.; Samsudeen, K.; Rajesh, M.K.; Sankaran, M.
The recent genetic resources explorations undertaken in Andaman Islands revealed the occurrence of coconut palms yielding soft endosperm among the natural coconut population called Thairu thengai or Nei thengai. The characterization of Thairu thengai accession from Andaman Islands using the in situ observations on seven palms revealed that the palms belong to tall group of coconut.The palms of this type bear fruits with both normal and soft endosperm.About 16 to 27 per cent of the fruits per bunch were observed to be with soft endosperm and the remaining ones were with normal firm endosperm. The normal nuts of the identified palms produced poor quality copra indicating some degree of softness. The soft endosperm fruits are of three types with difference in the layers of soft endosperm, nut water and firm endosperm. The palms are found to occur sporadically in South Andaman. Although these palms appear morphologically looking similar to other coconut palms except for endosperm trait, differences could be observed for many morphological and fruit component traits. The morphological and fruit component traits of Thairu thengai coconut are compared with the other other coconut populations. The strategies for conservation and utilization of this novel type of coconut are proposed.
Development and characterization of non‑coding RNA‑derived simple sequence repeat markers in coconut (Cocos nucifera L.)
(2022) sabana, A.A.; Ginny Antony; Rajesh, M.K.; Gangaraj K.P.; Niral, V.; Sudha, R.; Jerard, B.A.
Development of a RAPD-derived SCAR marker associated with tall-type palm trait in coconut
(2013) Rajesh, M.K.; Jerard, B.A.; Preethi, P.; Regi Jacob Thomas; Fayas, T.P.; Rachana, K.E.; Anitha Karun
Coconut palms are classified into two major types, viz. talls and dwarfs, based on plant stature. The selection of coconut seedlings in the nursery, presently relying solely on morphological markers, often results in selection of out-crossed seedlings. Hence, identification of molecular markers for distinguishing tall/dwarf character at an early stage of growth assumes importance. In the present investigation, a RAPD marker for tall-type palm trait was identified using a pooled DNA approach. Screening of tall and dwarf palm bulked DNA with 200 decamer primers revealed a primer OPA09, producing a unique band of around 260 bp exclusively in tall accessions. The primer was used for screening and validation in individual tall and dwarf coconut accessions representing different geographic regions. The band was present in all the tall accessions, but absent in the dwarfs. Furthermore, sequence characterized amplified region (SCAR) primers were designed from the unique RAPD amplicon. The primers produced a specific 260-bp amplicon in tall accessions, but not in dwarf accessions. The SCAR marker was utilized in assessing the purity of hybrid seedlings of D×T (Dwarf×Tall) cross. The results pave the way for ensuring genuineness/quality of hybrid seedlings of coconut.
Evaluation of Intercrops in Arecanut Gardens of South Andaman Island
(2019) Ajit Arun Waman; Maheswarappa, H.P.; Jerard, B.A.; Senthilkumar, T.; Gayatri Chakraborty
Genetic and phylogenetic relationships of coconut populations from Amini and Kadmat Islands, Lakshadweep (India)
(2014) Rajesh, M.K.; Samsudeen, K.; Jerard, B.A.; Rejusha, P.; Anitha Karun
A great deal of variability exists in coconut populations of the Lakshadweep group of islands in India, which is regarded as one of the likely centre s for coconut domestication. It is possible to gain insights into the evolution of coconut populations in these islands by undertaking detailed studies of these populations. In this study, the variability and phylogenetic relationships within populations of Laccadive Ordinary Tall (LCT) and Laccadive Micro Tall (LMT) from Amini and Kadmat Islands were studied using microsatellite markers. LCT collections from these two islands were earlier grouped, according to fruit shape, into three type s viz., elongated, round or oval shaped and pear shaped ones. Three accessions of LMT, one each from Amini and Kadmat, and a variant of LMT from Kadmat Island, characterized by the round shaped fruit and nut, were also used for the studies. Seedlings raised from these types were analysed using 20 highly polymorphic SSR markers. Elliptical type from Amini, which are described as Niu Kafa type, emerged as distinct from other populations and was related to round or Niu Vai type from Amini. Pear shaped type from both the islands, which was considered as the introgressed form, showed affinity and appear to have developed as a result of introgression between elliptical and round types. When the LMT palms were analyzed, the LMT palms from Amini and Kadmat clustered together, while the round variant of LMT from Kadmat Island was found to be distinct. A large extent of variations were also found among individual palms of these distinct types when analyzed using SSR markers, highlighting the importance of selection of LCT mother palms for hybrid seed production.
Heterosis for economic traits in coconut (Cocos nucifera L.)
(2018) Shinde, V.V.; Ghavale, S.L.; Maheswarappa, H.P.; Jerard, B.A.; Sumitha, S.
Horticulture Development in Lakshadweep Islands - status and strategies
(2019-04) Thamban, C.; Samsudeen, K.; Shameena Beegum; Jerard, B.A.
Hybridization Technique in Coconut
(CPCRI Kasaragod, 2009) Niral, V.; Jerard, B.A.; Samsudeen, K.; Nair, R.V.
Identification and utilization of informative EST-SSR markers for genetic purity testing of coconut hybrids
(2016-08) Preethi, .P; Rajesh, M.K; Rahul, C.U; Jerard, B.A.; Samsudeen, K; Regi Jacob Thomas; Anitha Karun
Coconut palms are categorized into two forms, viz., ‘talls’ and ‘dwarfs’ which are being utilized to produce hybrids through the process of inter-varietal or intra-varietal crosses. Hybrid coconut seedlings are generally identified and selected based on morphological traits by plant breeders, which is quite difficult and requires expertise. Even minor errors in identification may adversely affect breeding programs in coconut, which is spread over many decades. In this study, we have utilized thirty EST-SSR markers, derived from existing coconut leaf transcriptome data, for screening polymorphism between eighteen coconut parental lines. The polymorphic primers capable of differentiating the parental palms were then utilized successfully for assessment of purity of hybrids derived from these parents. Thus, the current study demonstrates the utility of EST-SSR markers in determining the genetic purity of hybrids in coconut.
Influence of variety and season in the inflorescence sap production in Cocos nucifera L.
(2013-04) Samsudeen, K.; Niral, V.; Jerard, B.A.; Mukesh Kumar; Sugatha, P.; Hebbar, K.B.
The unfermented inflorescence sap of coconut is nutritionally rich and is being popularized as a natural health drink. The present work was initiated to understand the influence of variety and season on the inflorescence sap production and its quality in selected varieties of coconut. Three varieties of coconut viz., West Coast tall (WCT), Laccadive Ordinary Tall (LCT) and Chawghat Orange Dwarf (COD) and one hybrid CODxWCT (Chandra Sankara) grown at CPCRI, Kasaragod were selected for the study during 2010 and 2011. The work was undertaken for four seasons viz., monsoon, post monsoon, winter and summer. The study revealed that tall varieties are better than dwarf varieties for sap production. Average sap production of 960 ml and 880 ml respectively, in WCT and DxT hybrids was the best among the varieties tested. Sap production in COD was very low and not suitable for tapping. Total sugar content in WCT (11.44 g 100 ml–1) was the highest among the varieties tested. DxT had high reducing sugar content (0.37 g 100 ml–1). The study also revealed that the best time for tapping is from the middle of monsoon to the beginning of winter season. Tapping should be avoided during summer months under rainfed conditions. The information generated is useful to the farmers for tapping of coconut palm by regulating the time of tapping, identifying suitable varieties and providing irrigation to increase sap production.
Island Ecosystems Host Rich Diversity in Coconut (Cocos nucifera): Evidences from Minicoy Island, India
(2017) Jerard, B.A.; Rajesh, M.K.; Regi Jacob Thomas; Niral, V.; Samsudeen, K.
Microsatellite variability of coconut accessions (Cocos nucifera L.) from Andaman and Nicobar Islands
(2008) Rajesh, M.K.; Nagarajan, P.; Jerard, B.A.; Arunachalam, V.; Dhanapal, R.
The extent of genetic diversity in 26 coconut accessions from the Andaman and Nicobar (A&N) Islands was determined using 14 microsatellite markers. A total of 103 alleles were detected by the microsatellite markers with an average of 7.35 alleles per locus. The average observed and expected heterozygosity was 0.29 and 0.66 respectively. A mean fixation index (FST) of 0.49 was observed, indicating a high level of population differentiation among the coconut accessions. Heterozygosity was highest in tall coconut accessions. Majority of rare alleles were observed in tall accessions from the Nicobar Islands. The UPGMA dendrogram revealed clustering of majority of tall and dwarf accessions separately. This study using microsatellites confirms the rich genetic diversity of coconut accessions from A&N Islands.

Browsing by Author "Jerard, B.A."

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