Inheritance Of Several Traits Research Articles

Phenotypic characters of rice landraces reveal independent lineages of short-grain aromatic indica rice.

Rice landraces are lineages developed by farmers through artificial selection during the long-term domestication process. Despite huge potential for crop improvement, they are largely understudied in India. Here, we analyse a suite of phenotypic characters from large numbers of Indian landraces comprised of both aromatic and non-aromatic varieties. Our primary aim was to investigate the major determinants of diversity, the strength of segregation among aromatic and non-aromatic landraces as well as that within aromatic landraces. Using principal component analysis, we found that grain length, width and weight, panicle weight and leaf length have the most substantial contribution. Discriminant analysis can effectively distinguish the majority of aromatic from non-aromatic landraces. More interestingly, within aromatic landraces long-grain traditional Basmati and short-grain non-Basmati aromatics remain morphologically well differentiated. The present research emphasizes the general patterns of phenotypic diversity and finds out the most important characters. It also confirms the existence of very unique short-grain aromatic landraces, perhaps carrying signatures of independent origin of an additional aroma quantitative trait locus in the indica group, unlike introgression of specific alleles of the BADH2 gene from the japonica group as in Basmati. We presume that this parallel origin and evolution of aroma in short-grain indica landraces are linked to the long history of rice domestication that involved inheritance of several traits from Oryza nivara, in addition to O. rufipogon. We conclude with a note that the insights from the phenotypic analysis essentially comprise the first part, which will likely be validated with subsequent molecular analysis.

The Inheritance of Several Traits in Three Diploid Interspecific Rose Populations

Seedlings from three interspecific backcross rose populations derived from a F1 population were used to study inheritance of several traits in roses. Three F1 plants (WOB13, WOB21, and WOB26) from the hybridization of the diploid parents Rosa wichuraiana and `Old Blush' were backcrossed to `Old Blush' to produced three populations to observe the segregation of several morphological and disease resistance traits. The segregating rose traits in the backcrosses are no prickles on stems, non-recurrent blooming habit, white single flowers, black spot resistance, and powdery mildew resistance present in the Rosa wichuraiana parent compared to prickles on stems, recurrent blooming habit, pink double flowers, black spot susceptible, and powdery mildew susceptible present in the `Old Blush' parent. Visual data was collected for the segregating traits using color standards and rating scales as appropriate. The three populations expressed the segregating traits to varying degrees. Under the environmental conditions at College Station, Texas the population `Old Blush' × WOB26 had a greater expression of the traits for no prickles on stems, recurrent blooming habit, disease resistance to black spot, and disease resistance to powdery mildew, which are traits desired in breeding programs. The segregation of flower color (white/pink), and flower type (single, semi double, and double) were similar in all three populations.

Evaluation of cytoplasmic effects on agronomic and seed quality traits in two doubled haploid populations of Brassica napus L.

Cytoplasmic effects have been occasionally implicated in the inheritance of several traits in oilseed rape (Brassica napus L.), including linolenic acid concentration (18:3) in the oil. It is important that these be considered when choosing the direction of cross for producing new breeding populations. To study this phenomenon, a reciprocal cross was made between two genotypes of oilseed rape, Reston and LL09, which differed for their erucic and linolenic acid concentrations in the seed oil. Two DH populations, which were produced by microspore culture from reciprocal F1 plants, were evaluated in the growth room for one generation and in the field at two locations in Southern Ontario in 1993and 1994. Field notes were taken on days to flower, days to maturity,plant lodging, plant height and, seed quality traits. In the growth room study, the phenotypic distribution of 18:3 differed significantly between the two reciprocal DH populations. In the field, significant reciprocal differences between the population means were detected for 18:3,flowering date and protein content in both years and for days to maturity and oil content in 1993 only. To further study the parental lines,chloroplast (cp) and mitochondrial (mt) DNA from parental lines were isolated and subjected to RFLP and RAPD analysis. Several random primers revealed reproducible DNA polymorphism (RAPD) between the parental mt DNA. It is concluded that the direction of cross should be taken into consideration by oilseed rape breeders relying solely on doubled haploids for developing genotypes with modified seed quality traits in Brassica napus L.

Inheritance of Selected Traits in Accessions of Vigna vexillata (L) a Rich of Australian and African Origin

The inheritance of several traits in Vigna vexillata was studied for crosses involving accessions of African and Australian origin. Anthocyanin stem pigmentation, silver leaflet midrib, leaflet hirsuteness, presence of long hairs on the calyx lobes, black pod colour, speckled seed testa and twining stem habit all appeared to be conditioned by single completely dominant gene action, as was apparent resistance to powdery mildew. Width of the floral standard, peduncle length, number of seeds per pod, weight of 100 seeds, tuberous root dry weight, total plant dry weight and harvest indices for seed and tuberous roots all appeared to be quantitatively inherited, with moderate broad sense heritabilities. Leaflet shape, the primary distinguishing attribute between the varieties occurring in Australia, angustifolia and youngiana, appeared to be simply inherited. No difficulties were encountered in obtaining F1 and backcross progenies in any crosses. Further, the inheritance of traits in progeny of Australian × African crosses appeared normal and, in the several instances where direct comparison was possible, similar to that observed in crosses within the Australian material.