SUMMARYThe induction of male sterility in wheat by application of Ethrel at different concentrations and times was investigated in glasshouse‐grown Triticum aestivum cv. Sirius. The results obtained agree with our previous findings, that to induce full sterility, Ethrel must be applied before meiosis is initiated in the oldest florets of the ear. However, to ensure full emergence of sterilized ears, the application has to be made as close to this stage as possible using a concentration of between 1000 and 2000 ppm. Ethrel application thus shows promise as a method for detecting heterotic combinations by producing sufficient F1 seed for small‐scale field trials.
Quantity and composition of epicuticular leaf wax of Euphorbia dendroides L. was examined. The wax contained rt-alkanes, wax esters, aldehydes, fatty acids and primary alcohols. In addition to these common epicuticular wax constituents several triterpenoids and benzoic acid esters were found. The triterpenols β-amyrin and lupeol occurred free as well as esterified with long chain fatty acids. The ketones Δ 12-oleanen-3-one and lupen-3-one have also been identified.
This work reports on the production and yield assessment of F1 wheat hybrids from crosses between cytoplasmic male sterile lines, with Triticum timopheevi cytoplasm, and cultivars with fertility restoring genes.In four years of trials conducted between 1974 and 1977, only three F1 hybrids out of a total of 168 yielded significantly more than the control variety 'Maris Huntsman', which currently occupies a substantial proportion of the area planted with winter wheat in the UK. Because of the rapid increase in yield of conventional wheat varieties, which has already led to varieties which outyielded 'Maris Huntsman', the yield advantage of these F1 hybrids is insufficient for them to be developed as commercial varieties.The efficient production of uncontaminated male sterile and F1 seed presents problems of isolation and a difficult biological problem in increasing the cross breeding potential of maintainer and restorer lines. These together with selection for other parental characters such as restoration, short straw and resistance to sprouting make the development of F1 hybrids more difficult and expensive than that of conventional varieties.
SUMMARYThe induction of male sterility with ethephon and improvement in ear emergence with GA3 (1‐1 kg a.i./ha) applied 3 days later, was investigated in the winter wheat cv. Maris Nimrod sown in the field at72, 138 and 276 spaced plants/m2. Increased sowing density resulted in fewer surviving tillers per plant, a larger number of tillers per unit area and consequently a narrower range of stage of tiller development. This permitted a more accurate assessment of the correct time for ethephon application and resulted in a larger proportion of tillers responding to GA3 by having fully emerged ears. The most effective treatments for the production of emerged male sterile ears were 6‐4 and 12‐8 kg ethephon/ha applied to crops sown at the highest density.
Quantity and composition of epicuticular wax of Euphorbia aphylla were examined. The wax contained the common lipid components «-alkanes, wax esters, pr. alcohols, fatty acids and in traces aldehydes and acetates all occurring in homologous series. Additionally, several triterpenols such as ß-amyrin, a-amyrin, lupeol and simiarenol were found. With the exception of simiarenol these triterpenols occurred free as well as esterified with acetic acid and fatty acids. The ketones, oleanen-3-one, ursen-3-one and lupen-3-one have also been identified.
Ethrel at a concentration of 2000 pprn active ingredient (ai.), applied to the spring wheat cv. Sirius before meiosis was initiated in the oldest florets of the ears, induced almost complete male sterility but prevented full ear emergence. Concentrations of 100,200 and 300 ppm a.i. GA,, applied 2 or 5 days after the Ethrel, were equally effective in promoting full emergence of * Present address : Cotton Research Institute, Sindos, Thessaloniki, Greece. 310 W. G. HUGHES AND OTHERS per block. The application time (To) was chosen to coincide with a mean stage of anther development just before meiosis. This was judged approximately, using stems sampled from guard row pots, and previous experience of the relationship between degree of flag leaf emergence and ear size.Gibberellic acid (Berelex, 90 % GA,, Plant Protection Ltd, Fernhurst, Haselmere, Surrey, England) was applied 2 (time T,), and 5 (time T2) days later at rates of 0, 100, 200 and 300 ppm a.i., each ratex time combination being applied to one randomly chosen Ethrel-treated pot and one non-Ethrel-treated pot in each block.Plants to be sprayed were removed from the sand benches and stood on the glass-
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.