Transmission of somaclonal variation in wheat

Summary Transmission of somaclonal variation was studied in callus derived (SC1) plants of wheat, Triticum aestivum L. Second (SC2), third (SC3) and fourth (SC4) generations were compared with those obtained from embryo culture (E1-E4). SC2 generation had significantly lower grain yield (–37.3%), reduced thousand kernel weight (–7.8%) and shorter height (–2.1%) than that of E2, and included 5.7% seed-sterile and 15.0% partially seed-sterile plants. SC3 generation showed reduced yield (–12.6%), lower thousand kernel weight (–4.9%) and shorter plant height (–1.9%) than E3 generation. SC4 progeny of a short height, partially sterile SC1 variant included aberrant plants: a haploid, few aneuploids, mixoploids, some showing multiploidy, spindle abnormalities, multivalents, bridges and fragments, and tillers having supernumerary spikes with branched rachis. Somaclonal variation resulted from genome instability in callus, and likely involved transposable elements.