Natural polyploidy in amaranths (Amaranthus spp.)

摘要

Polyploidy means the heritable condition of having more than two complete sets of chromosome and is counted as an important evolutionary and speciation process in many plants and some animals. Amaranthus is a genus up to 60 species and shows a wide range of morphological diversity, of which for some researcher remain as a puzzle. It is a kind of multipurpose plants, whose grains and leaves are highly nutritious. Leaves are mostly consumed in tropical lowlands of developing countries, including in Indonesia. Based on morphological studies in Indonesian amaranths were found a high variability of morphological variation in the Indonesian weedy of Amaranthus dubius Mart. Ex. Thell. It may exist as diploid (n = 16 or n = 17) or as tetraploid in the nature. The objective of this study is to investigate the polyploidy level of 87 accessions consisting of grain, vegetable, ornamental, and weedy of Amaranthus, which is pre-requisite for future breeding and propagation efforts of vegetable amaranth. This is the first result reported the polyploidy in Amaranthus based on a flow cytometer. No tetraploid of A. dubius was found in this study albeit higher morphology observed in the collection. The chromosome number varied between 2n = 32 or 2n = 34 in most of grain, vegetable, and weedy amaranths. No polyploidy level detected in A. dubius in this collection may open a new possibility to breed a new variety of amaranths with desired characteristics.