Evaluating Parents and Prediciting Performance of Synthetic Alfalfa Varieties

One hundred random clones from \u27Cherokee\u27 alfalfa (Mediccigo sativa L.) were evaluated by self-(S,), topcross-, and clonal-progeny tests. Clonal progenies were most effective, topcross progenies moderately effective, and S, progenies the least effective in predicting first-cross yield. Forage yield was mostly independent of self-fertility. Nine clones were selected for yielding ability based on the progeny tests. The nine clones, their S, families, the diallel set of single-cross families from the nine clones, and the Syn 1 and Syn 2 generations of 10 synthetic varieties from the nine clones were evaluated. The best single-cross family yielded 150 7c; the best Syn 1 yielded 132 % ; and the best Syn 2 yielded 116% of \u27Cherokee\u27. The predicted yield of the best synthetic possible among the nine clones in the equilibrium generation (Syn 4 and beyond) was 109 \u27I( of \u27Cherokee\u27. The Syn 2 yields were predicted with 94 % , 91 % , and 851/o accuracy (as measured by regression analysis) from formulas based on diallel-cross yields, general-combining-ability yields, and clonal yields, respectively, coupled with S, family yields and coefficients of inbreeding. The coefficients of inbreeding alone could account for more than 80 % of the variation among Syn 2 varieties. The negative effect of inbreeding and gene recombination on advanced generations was apparent. Only a few of the 502 synthetic varieties possible from the 9 selected clones were predicted to outyield \u27Cherokee\u27 in the equilibrium generation. The prediction formulas will allow one to determine with reason-able accuracy (1) the number of clones to include in a synthetic variety, (2) the parents that are likely to produce the best possible variety, and (3) the quantity that the variety will yield in the generation the farmer plants. KEY WORDS: breeding, breeding Medicago sativa L., heterosis, inbreeding depression, Medicago sativa L., plant breeding

Polyphenols act synergistically with doxorubicin and etoposide in leukaemia cell lines

The study aimed to assess the effects of polyphenols when used in combination with doxorubicin and etoposide, and to determine whether polyphenols sensitised leukaemia cells, causing inhibition of cell proliferation, cell cycle arrest and induction of apoptosis. This study is based on findings in solid cancer tumours, which have shown that polyphenols can sensitize cells to chemotherapy, and induce apoptosis and/or cell-cycle arrest. This could enable a reduction of chemotherapy dose and off-target effects, whilst maintaining treatment efficacy. Quercetin, apigenin, emodin, rhein and cis-stilbene were investigated alone and in combination with etoposide and doxorubicin in two lymphoid and two myeloid leukaemia cells lines. Measurements were made of ATP levels (using CellTiter-Glo assay) as an indication of total cell number, cell cycle progression (using propidium iodide staining and flow cytometry) and apoptosis (NucView caspase 3 assay and Hoechst 33342/propidium iodide staining). Effects of combination treatments on caspases 3, 8 and 9 activity were determined using Glo luminescent assays, glutathione levels were measured using the GSH-Glo Glutathione Assay and DNA damage determined by anti-γH2AX staining. Doxorubicin and etoposide in combination with polyphenols synergistically reduced ATP levels, induced apoptosis and increased S and/or G2/M phase cell cycle arrest in lymphoid leukaemia cell lines. However, in the myeloid cell lines the effects of the combination treatments varied; doxorubicin had a synergistic or additive effect when combined with quercetin, apigenin, emodin, and cis-stilbene, but had an antagonistic effect when combined with rhein. Combination treatment caused a synergistic downregulation of glutathione levels and increased DNA damage, driving apoptosis via caspase 8 and 9 activation. However, in myeloid cells where antagonistic effects were observed, this was associated with increased glutathione levels and a reduction in DNA damage and apoptosis. This study has demonstrated that doxorubicin and etoposide activity were enhanced by polyphenols in lymphoid leukaemia cells, however, differential responses were seen in myeloid cells with antagonistic responses seen in some combination therapies