Genome analysis in the genus Amatanthus
| dc.contributor.advisor | Peter, K V | |
| dc.contributor.author | Mallika, V K | |
| dc.contributor.author | KAU | |
| dc.date.accessioned | 2019-10-01T05:31:00Z | |
| dc.date.available | 2019-10-01T05:31:00Z | |
| dc.date.issued | 1987 | |
| dc.description | PhD | en_US |
| dc.description.abstract | Cytogenetical studies on eight Amananthiu species, viz., A. inicot-Qn./ A. JUvvduA/ A. vajujcLaa, A, ApAnoAUA, A, cLliAallA, A,hypochondmacuA, A. cnuentuA and/4, caudaiiu and their hydrids were undertaken to understand their genome relationship, phylogeny and evolution. The development and arrangement of flower cluster In AmcuiardhuA were analysed microscopically and discussed in detail. A simple provisional key was developed for Identification of the eight species as the existing keys were complex and confusing. The eight species were also evaluated for their photoperiodlc requirements and antinutritional factors. Meiotic studies revealed that members of section Blitopsis had x = 17 while section Amaranthus had x = 16 and 17. A.duLuu a polyploid with n = 32 behaved as an allopolyploid. Mean number of chiasmata/bivalent was maximum in the cultivated species and minimum in the semiwild species, A ,apaiioaua which also had maximum number of rod bivalents. Pollen grains of varying sizes (Macro and medium) were observed In all the species. The cultivated species were characterised by bigger chromosomes and pollen grains. Interspecific hybridization was attempted in all possible combinations but many of the crosses failed. A few failed crosses exhibited seedling mortality. Seven interspecific hybrids grew and flowered and these included hybrids within and between sections Blitopsis and Amaranthus. A .IavaduA x. A, ioAcolon. the only interspecific hybrid within Blitopsis resembled mostly the male parent but was highly sterile. Cytologlcal studies revealed the presence of two or more Interchanges involving 3-6 chromosomes and subsequent melotic abnormalities resulted in 90% pollen sterility. The interspecific hybrids within section Amaranthus included A.^p-moAiUyA^nHinA A , ApmoALLb x A.hypochoncbuxLCLU,, A ,4 p m o 4 iu x A , c a u d a iiu t A, A p in o itu x A, c A u & n iiu , and A, c A ii& n tiu x A. c a u d a iiu . The hybrid A .c /u ie n iiu x A,caudaiiu produced only female flowers in the stunted and deformed hybrid plant. Other hybrids exhibited a preponderance of AupinoAtu characters indicated by presence of spines, reduction in inflorescence size, distinct placement of male and female flowers etc. Cytological studies revealed the presence of 1-2 multivalents including 3-4 chromosomes, moderate frequency of bivalents, and a low frequency of univalents in the hybrids. Chromosomal repatterning through translocations and inversions are also involved in speciation within both sections Blitopsis and Amaranthus. A, 6p u \.0Auu x A, v ia m L u , the first success of hybridization between the two sections resulted in a short and sturdy hybrid plant with dominating A.qunoMu characters. Cytological studies revealed that PMCs had high frequency of bivalents and only low frequency of univalents. The complete absence of multivalents indicated that cryptic structural changes and genetic drift are only involved In the cytogenetic differentiation of 2 the two species. D analysis of data of chromosome associations In interspecific hybrids at metaphase I indicate the clustering of hybrids within and between sections under the same group. This as well as morphological studies questions the validity of the naturalness of the two sections in AmaAO/iiJvu, The 40 accessions available in the germplasm were classified into different species based on detailed cytomorphological studies. Twenty one species were ascribed to A, four to A. d u J L u u and 15 to A. h y p o c h o n d b u j a c iiA , The reasons for low seed recovery in the A ,b u £ .o £ o A . accession A- were also studied. Investigations on photoperiodic response of the different species indicated that there is precocious flowering with increase in photoperiod in A. h y p o c h o r u d j u x L c i u , A, riidLuu and A, A p A n o A t u , Flowering was delayed with more light in A, cniirlatiu, and A, iju.c.o&QJi while A, cAuentu& and A, v u u x L l a were photoinsensitive. The content of antinutrient factors in the tender leaf and stem varied from 3.60 to 5.10% for oxalate and 0.295 to 0.695% for nitrate in the different species. In general Blitopsis had higher content of antinutrients than section Amaranthus, the only exception being A, A p .in .o A u A of section Amaranthus. The primitiveness of A ,apjjioaua was evident from the present studies. This pantropical cosmopolitan weed has played a major role in the evolution of otherAmoAaniAuAspp. Evidences were also obtained on the origin of vegetable amaranths from grain amaranths. | en_US |
| dc.identifier.uri | http://krishikosh.egranth.ac.in/handle/1/5810129943 | |
| dc.keywords | Olericulture | en_US |
| dc.language.iso | en | en_US |
| dc.pages | 104p. | en_US |
| dc.publisher | Department of Olericulture, College of Horticulture, Vellanikkara | en_US |
| dc.sub | Horticulture | en_US |
| dc.subject | null | en_US |
| dc.theme | Genome analysis | en_US |
| dc.these.type | Ph.D | en_US |
| dc.title | Genome analysis in the genus Amatanthus | en_US |
| dc.type | Thesis | en_US |