Genotype and phenotype variability of BC1F1 progenies from backcross of C3 and Koshihikari

Improvement of local rice variety could be conducted by crossing it with superior varieties. C3 is improved line of Acehnese rice ‘Cantik Manis’ by crossing it with the introduced Chinese rice variety Yin Zhan to make their progenies have shorter lifespan and good productivity. Although C3 line has been improved, this variety still has lifespan for about ± 135 days. Koshihikari is Japanese rice variety with its lifespan about 80-90 days. It is though that Koshihikari has various semidwarf gene such as sd-1 or other semidwarf genes. The strategy that can be used to decrease harvesting period of C3 is by crossing this variety with Koshihikari to insert semi-dwarf gene such as sd-1. The research was conducted to analyse the existing of sd-1 gen and phenotypic performance of their progenies specially in BC1F1. The seed of BC1F1 were found by crossing 2 prospective F1 plants (T8 and T10) with C3 parent. Molecular analysis showed that the whole progenies BC1F1-T8 inherit sd-1 gene (100%). Phenotypic observation showed the whole progenies had similar architecture as their parents with average heights at 45 DAP ranged from 74-91 cm, and number of tiller range from 3-9 tillers. Whereas in BC1F1-T10 progenies, there were 11 plant from 12 plants inherit sd-1 gene (91.7%). These progenies had average heights at 45 DAP ranged from 75-88 cm, and number of tiller range from 6-13 tillers.

‘Green revolution’ dwarf gene sd1 of rice has gigantic impact

Rice (Oryza sativa L.) is one of the most important cereal that has fed the world over a longer period. Before green revolution, cultivated rice is believed to have consisted of thousands of landraces each adapted to its specific climatic conditions by surviving against different abiotic and biotic selection pressure. However, owing to the low yield, photo-period sensitivity, late maturity and sensitivity to lodging of these landraces grown world-wide, serious concerns of impending global food crisis was felt during the 1960s because of (i) unprecedented increase of the population and (ii) concomitant decline in the cultivable land. Fortunately, high-yielding varieties developed through the introgression of the semi-dwarf1 gene (popularly known as sd1) during the 1960s led to significant increments in the food grain production that averted the apprehensions of nearing famine. This historical achievement having deep impact in the global agriculture is popularly referred as ‘Green Revolution.’ In this paper, we reviewed, its genetics as well as molecular regulations, evolutionary relationship with orthologous genes from other cereals as well as pseudo-cereals and attempted to provide an up-to-date information about its introgression to different rice cultivars of the world.

Genetics of Height and Branching in Faba Bean (Vicia faba)

A better understanding of the genetics of plant architecture, including height and branching, could improve faba bean breeding for varieties with better fit into specific cropping systems. This study aimed to determine the inheritance and genetic interactions of the sources of the dwarf gene (dwf1) and semi-dwarf gene (dwarf1), and to investigate the genetics of branching in the faba bean. We chose inbred lines IG 12658 (dwarf, carrying dwf1) and Rinrei (semi-dwarf, carrying dwarf1) along with Aurora/2 and IG 114476 as sources of non-dwarf faba bean genotypes and crossed them (Aurora/2 × IG 12658, IG 114476 × IG 12658, Rinrei × IG 12658, IG 114476 × Rinrei, and Rinrei × Aurora/2). IG 114476 was also used as a genetic source of a highly branching phenotype and crossed with IG 12658, Rinrei, and Aurora/2 to study the genetics of branching. Parental lines, F1s, and F2 populations were evaluated under growth chamber and field conditions in 2018. The segregating F2 populations were tested for 3:1 single recessive gene inheritance using Chi-square tests. Both dwarfing/semi-dwarfing genes fit 3:1 recessive, and 15:1 for double recessive. Rinrei was not a true dwarf, and the gene creating the dwarf appearance reduced the initial growth rate, but this corrected over time. Multiple F2 populations were also tested for a 3:1 single dominant gene hypothesis for highly branched phenotypes. These populations showed a bell-shaped phenotypic distribution for branch number, with no discernable classes, and revealed that branching was likely quantitatively controlled. In conclusion, dwarfism and branching in faba bean were controlled qualitatively and quantitatively, respectively.

Cloning and Functional Analysis of Dwarf Gene Mini Plant 1 (MNP1) in Medicago truncatula

Plant height is a vital agronomic trait that greatly determines crop yields because of the close relationship between plant height and lodging resistance. Legumes play a unique role in the worldwide agriculture; however, little attention has been given to the molecular basis of their height. Here, we characterized the first dwarf mutant mini plant 1 (mnp1) of the model legume plant Medicago truncatula. Our study found that both cell length and the cell number of internodes were reduced in a mnp1 mutant. Using the forward genetic screening and subsequent whole-genome resequencing approach, we cloned the MNP1 gene and found that it encodes a putative copalyl diphosphate synthase (CPS) implicated in the first step of gibberellin (GA) biosynthesis. MNP1 was highly homologous to Pisum sativum LS. The subcellular localization showed that MNP1 was located in the chloroplast. Further analysis indicated that GA3 could significantly restore the plant height of mnp1-1, and expression of MNP1 in a cps1 mutant of Arabidopsis partially rescued its mini-plant phenotype, indicating the conservation function of MNP1 in GA biosynthesis. Our results provide valuable information for understanding the genetic regulation of plant height in M. truncatula.