Selective control of creeping bentgrass (Agrostis stolonifera) is desirable when it has escaped into other turfgrasses. The objective of this study was to evaluate the influence on creeping bentgrass control from adding urea ammonium nitrate (UAN) to mesotrione plus non-ionic surfactant (NIS) spray solution, and raking to remove dead tissues of creeping bentgrass. A 2-year field study was conducted with a split-plot design, where raking was the whole plot treatment and herbicide was the sub-plot treatment. Herbicide treatments included application of mesotrione at 56 and 70 g·ha−1 singly and sequentially with 0.25% (v/v) NIS or 0.25% (v/v) NIS plus 2.5% (v/v) UAN solution. Sequential applications were made three times on a 2-week interval. Removing the dead clippings by raking improved the creeping bentgrass control from 60% to 73% averaged over rates, timings, adjuvants, and years. Adding UAN to NIS plus mesotrione improved creeping bentgrass control from 78% to 98% with three sequential applications at 70 g·ha−1.
Lijuan Xie, Deying Li, Wenjuan Fang, and Kirk Howatt
Hai-nan Liu, Jian-rong Feng, Xiao-fang Liu, Wen-hui Li, Wen-juan Lv, and Ming Luo
Three kinds of expression vectors of a pollen-S determinant were constructed to provide a reference for molecular breeding of self-compatible (SC) Prunus species. An S-haplotype-specific F-box (SFB) protein gene from the ‘Xiaobaixing’ apricot (Prunus armeniaca) was cloned by reverse transcription polymerase chain reaction (RT-PCR) and 3′-rapid-amplification of cDNA ends (3′-RACE). A 1136-bp sequence complementary to the 3′-end of the cDNA (GenBank accession number KP938528.2) with a 912-bp complete open reading frame (ORF) was obtained. The deduced amino acid sequence contained an F-box domain, two variable regions, and two hypervariable regions with structural characteristics similar to SFB in other Rosaceae plants. Sense, antisense, and RNA interference (RNAi) vectors for SFB were constructed by enzyme restriction. The target fragment was restricted using the corresponding restriction enzyme and then directionally inserted between the 35S cauliflower mosaic virus promoter and the nopaline synthase terminator (NOS-ter) of the expression vector pCAMBIA-35S-MCS-NOS-NPTII. The intron-containing hairpin RNA (ihpRNA) was obtained by fusion PCR. The constructed vectors were transferred into Agrobacterium tumefaciens strain LBA4404 by freezing/thawing. The RNAi vector of SFB was also transformed in tobacco (Nicotiana tabacum). The successful construction of these three expression vectors provides a basis for transforming ‘Xiaobaixing’ apricot and the breeding of SC Prunus cultivars.