Lycoris wulingensis, a dwarf new species of Amaryllidaceae from Hunan, China

Lycoris wulingensis S.Y. Zhang, a new species from Hunan Province (central South China), is described and illustrated. This new species is a fertile diploid plant and its karyotype is 2n = 22. It is most similar to L. × haywardii in morphology, but the latter is a hybrid species and distributed in East China and the plant is much larger. Amongst the original species, L. wulingensis is similar to L. radiata, but differs from it in its flowers being rose-red (vs. red) and stamens and tepals are nearly the same length (vs. stamens significantly longer than tepals).

Identification and Characterization of a Loquat Aneuploid with Novel Leaf Phenotypes

A loquat (Eriobotrya japonica) seedling obtained from an open-pollinated triploid variety ‘Wuheguoyu’ (2n = 3x = 51) was verified as aneuploid and designated H39. It was shown to have five extra chromosome copies (2n = 39) compared with the diploid plant (2n = 2x = 34), one additional copy each for the 2nd, 4th, 7th, 9th, and 11th chromosomes. A number of novel features of leaf morphology was observed for H39 in comparison with ‘Ruantiaobaisha’ (2x, female progenitor) and ‘Wuheguoyu’ (3x, female parent), including increased leaf width, reduced leaf thickness, and narrowed palisade mesophyll and wax coat. Total chlorophyll content in unit area of H39 leaves was close to or slightly less than the diploid and triploid parent lines. Chlorophyll content in unit mass showed the opposite trend, with H39 having higher amount than the 2x and 3x. As we expected, H39 had the lowest net photosynthetic rates among the three lines. Furthermore, 8-month-old scions of H39 grew more slowly than those of the diploid and triploid lines, especially in plant height, which was much reduced (P < 0.01). These results indicated that the aneuploid H39 was a potential germplasm for breeding dwarfing loquat rootstock or interstock.

Induksi Tetraploid Tunas Pucuk Jeruk Siam Simadu (Citrus nobilis Lour) Menggunakan Kolkisin secara In Vitro

Seedless fruit is one of the criteria (necessary) to improve the quality of Simadu tangerine. The most effective method to obtain seedless triploid cultivars is hybridisation between tetraploid and diploid parents. Simadu tangerine is a diploid plant. Tetraploid Simadu tangerine can be obtained with doubling chromosome using colchicines.The aim of this research was to obtain tetraploid Simadu tangerine shoot which would serve as parent to produced seedless Simadu tangerine. Shoot-tips of Simadu tangerine without leaves were treated with colchicines at four different concentrations (0, 0.1, 0.2, and 0.3%) for 3 hours. The results showed that the high concentration of 0.3% reduced survival rate. The colchicine treatments reduced growth of shoot-tip of Simadu Tangerine.The leaves of colchicines treated shoots were thicker than control. Leaves from control (0% colchicine) and 0.1% colchicine treated shoots had 8.67 and 18.25 chloroplast per pair of guard cells. Compared to those of control, leaves with 0.1% colchicine had lower stomatal density, and larger stomatal size. It appeared that 0.1% colchicine treatment resulted in tetraploid Simadu Tangerine Shoot.<br />Keywords:chloroplasts, doubling chromosomes, stomatal size, stomatal density

SNiPloid: A Utility to Exploit High-Throughput SNP Data Derived from RNA-Seq in Allopolyploid Species

High-throughput sequencing is a common approach to discover SNP variants, especially in plant species. However, methods to analyze predicted SNPs are often optimized for diploid plant species whereas many crop species are allopolyploids and combine related but divergent subgenomes (homoeologous chromosome sets). We created a software tool, SNiPloid, that exploits and interprets putative SNPs in the context of allopolyploidy by comparing SNPs from an allopolyploid with those obtained in its modern-day diploid progenitors. SNiPloid can compare SNPs obtained from a sample to estimate the subgenome contribution to the transcriptome or SNPs obtained from two polyploid accessions to search for SNP divergence.

Probability of a recombinant inbred diploid plant for two linked genes

For some discreet traits, breeders may need to break genetic linkage between a desirable trait and an undesirable trait. Breeders need to be able to determine the minimum number of plants to grow to have a specified probability of identifying at least one plant that is recombinant between two linked loci. Since 1931, recurrence equations have been available to determine the genotypic frequencies of each genotype when two loci are linked as the level of inbreeding changes. However, these genotypic frequencies have not been published in a tabular form that would be helpful to the applied plant breeder. The objectives are to: (1) provide genotypic proportions as the intensity of linkage and the level of inbreeding increases; (2) determine the most efficient method of identifying a homozygous recombinant genotype as the level of inbreeding and linkage intensity are varied. Numerical examples and formula are provided to determine the number of plants that must be grown to have a given probability of success of identifying a specified number of recombinant types. For close linkage, the number of plants that must be genotyped is greatly decreased by waiting until the population is highly inbred. Key words: Genetic recombination, inbreeding