ABSTRACT
Plumbago indica L. contains a valuable bioactive compound called plumbagin. Elicited regenerated shoots grown in vitro could be another source of high-yielding plumbagin. The purpose of this investigation was to examine the effects of elicitor type and concentration, as well as elicitation period, on plumbagin content in in vitro-regenerated shoots of P. indica. Nodal explants were cultured on Murashige and Skoog (MS) medium containing 1 mg/L benzyladenine (BA) in combination with 0-150 mg/L yeast extract or 50-150 µM salicylic acid for four weeks. Plumbagin levels of 3.88 ± 0.38% and 3.81 ± 0.37% w/w g dry extract were achieved from the 50 and 100 mg/L yeast extract-elicited shoots, which were higher than the value obtained for the control. However, the addition of salicylic acid did not increase the plumbagin content. In the elicitation period experiment, nodal explants were cultured on MS medium supplemented with 1 mg/L BA and 50 mg/L yeast extract for durations of three, four and five weeks. The 4-week yeast extract-elicited shoot had a maximum plumbagin content of 3.22 ± 0.12% w/w g dry extract, greater than that of the control. In summary, the plumbagin content of the in vitro P. indica shoots was enhanced by 4-week elicitation using 50 mg/L yeast extract.
ABSTRACT
Improving sweet-waxy corn hybrids enriched in carotenoids via a hybrid breeding approach may provide an alternative cash crop for growers and provide health benefits for consumers. This study estimates the combining ability and heterosis of sweet-waxy corn hybrids for yield-related traits and carotenoids. Eight super sweet corn and three waxy corn lines were crossed to generate 24 F1 hybrids according to the North Carolina Design II scheme, and these hybrids were evaluated across two seasons of 2021/22. The results showed that both additive and non-additive genetic effects were involved in expressing the traits, but the additive genetic effect was more predominant. Most observed traits exhibited moderate to high narrow-sense heritability. Three parental lines, namely the ILS2 and ILS7 females and the ILW1 male, showed the highest positive GCA effects on yield-related traits, making them desirable for developing high-yielding hybrids. Meanwhile, five parental lines, namely the ILS3, ILS5, and ILS7 females and the ILW1 and ILW2 males, were favorable general combiners for high carotenoids. A tested hybrid, ILS2 × ILW1, was a candidate biofortified sweet-waxy corn hybrid possessing high yields and carotenoids. Heterosis and per se performance were more positively correlated with GCAsum than SCA, indicating that GCAsum can predict heterosis for improving biofortified sweet-waxy corn hybrid enriched in carotenoids. The breeding strategies of biofortified sweet-waxy corn hybrids with high yield and carotenoid content are discussed.
ABSTRACT
Dioscorealide B is an important secondary metabolite isolated from Dioscorea membranacea Pierre ex Prain & Burkill. The effect on secondary metabolite content of different concentrations of two elicitors [jasmonic acid (JA) and salicylic acid (SA)], and of medium status and JA exposure period were investigated. In the JA and SA concentration experiment, 6-week-old shoots were cultured on MS medium supplemented with 8.87 µM BA (6-benzyladenine) in combination with 100-500 µM JA or 50-200 µM SA for 3 weeks. MS medium supplemented only with 8.87 µM BA was used as a control. The highest dioscorealide B content was recorded in the 100 µM JA shoots. To determine the optimal medium status and JA exposure period, shoots were cultured on solid and in liquid MS media supplemented with 8.87 µM BA and 100 µM JA for 2, 3, 4 and 5 weeks. No interaction was found between the medium status and the elicitor exposure period in the dioscorealide B production. Shoots cultured on the solid MS medium supplemented with 100 µM JA had a higher dioscorealide B content (0.57 ± 0.35% w/w) than those cultured in liquid medium (0.36 ± 0.40% w/w) and 5-week JA exposure produced the highest dioscorealide B content of 1.05 ± 0.15% (w/w).
