Micro-Tuber Production in Diploid and Tetraploid Potato after Gamma Irradiation of <i>in Vitro</i> Cuttings for Mutation Induction

Abstract

Micro-tubers are important propagules in potato breeding and potato production, and they are also dormant and easily transported and therefore good targets for mutation induction in potato mutation breeding. A prerequisite for mutation breeding is to determine optimal mutation treatments. Therefore, radio-sensitivity tests of a tetraploid and a diploid potato to gamma irradiation were undertaken. Effects of different gamma sources on radioactivity were also studied. In vitro potato cuttings were gamma irradiated using a wide dose range (0, 3, 6, 9, 12, 15 and 20 Gy). The irradiated cuttings were then cultured to induce micro-tubers directly in vitro. Microtuber morphotypes were assessed after irradiation of cuttings using three gamma sources with emission activities of 1.8, 7.07 and 139 Gy/min. The diploid species (Solanum verrucosum) was more radio-sensitive than the tetraploid cultivar Desirée (Solanum tuberosum). Gamma dose rates had significant influences on subsequent micro-tuber production at various mutant generations. Effects included reductions in the number, size and weight of micro-tubers produced. Gamma dose was more lethal for the diploid potato genotype and micro-tubers produced were small compared to those produced by the tetraploid genotype after irradiation. Different treatments are recommended for diploid and tetraploid potato irradiation in producing large mutant micro-tuber populations.

Assessment of the Ploidy Level Diversity by Chloroplast Counts in Stomatal Guard Cells of Potato (Solanum tuberosum L.) Mutants

“…The variation in distribution of chloroplast counts in stomatal guard cells in the genotypes within a species may be due to the differential genotypic responses on the physical and biochemical tissue contents such as size, water content, DNA content, nuclear volume as a result of mutagen effects which are random [17,22,16,23]. The chloroplast counts distribution in M 1 V 1 generation in the three mutant populations was found to differ for diploids, triploids and tetraploids compared with M 1 V 2 and M 1 V 3 generations.…”

“…A radio-active cobalt-60 ( 60 Co) (gamma source) with a low dose rate of 2 gray per minute (Gy/min) were used to induce mutations. The optimal dosage for mutation induction, GR 30 and GR 50 (30% and 50% growth reduction respectively) as well as LD 30 and LD 50 (30% and 50% lethality dose) were determined for each approach as described by Owoseni et al [17], Mba et al [18], Kodym et al [19], Bado et al [16] to assess the susceptibility of each potato cultivar with regard to gamma irradiation. Two invitro radio-sensitivity tests were developed involving different tissues for irradiation of potato mutation induction as described by Bado et al, [20].…”

“…Kenya Sherekea has intermediate dormancy, highly tolerant to late blight and viruses, good storability, medium eye depth, red skin colour and oblong or round high tuber number per plant that matures between 105 -120 days yielding between 40 -50 t/ha [15]. A total of 30 tubers each of the three potatoes were sent to the Plant Genetics and Breeding Laboratory (PGBL) at IAEA/FAO Laboratories, Seibersdorf, Austria, where they were grown at the greenhouse to initiate in vitro shoot cultures as described by Bado et al [16].…”

CIERMMI Women in Science Biological, Humanities and Social Sciences

“…Similarly, those positive for E. canis, 87.6% had thrombocytopenia. Diaz et al (2016), evaluated a population of 200 domestic dogs from Molas, Yucatan, Mexico, 70% were infested with 1,116 R. sanguineus ticks. In addition, a prevalence of E. canis of 71% was calculated.…”

Analysis of Genetic Variability of Potato Induced Mutants Using Simple Sequence Repeat (SSR) Markers

“…A total of 160 potato mutants at M1V4 generation tubers generated from three potato varieties (Asante, Kenya Mpaya and Kenya Sherekea) that were irradiated from at different dose rates of gamma rays at Co 60 source at Seiberdorf laboratories in Vienna, Austria at 0, 3, 6, 9, 12 and 15 gray (Gy) for Asante, 0, 5, 6, 10 and 15 Gy for Kenya Mpya and 0, 3, 5, 10, 12, 15, 20, and 30 Gy for Kenya Sherekea [17,18,19]. The tubers were planted at the University of Eldoret, Biotechnology Green House Research facility to raise plants to be used for DNA extraction.…”