Vinod K. Shivrain

Syngenta · Research and Development

We conducted a greenhouse study to evaluate the differential response of Palmer amaranth to glyphosate and mesotrione and to quantify the level of tolerance to mesotrione in recalcitrant (difficult-to-control) accessions and their offspring. Seeds were collected from 174 crop fields (corn, cotton, and soybean) across Arkansas between 2008 and 2016....

Seed dormancy allows weedy rice ( Oryza sp.) to persist in rice production systems. Weedy and wild relatives of rice ( Oryza sativa L.) exhibit different levels of dormancy, which allows them to escape weed management tactics, increasing the potential for flowering synchronization, and therefore gene flow, between weedy Oryza sp. and cultivated ric...

Herbicide resistant weeds have been observed since the early years of synthetic herbicide development in the 1950's and 1960's. Since that time there has been a consistent increase in the number of herbicide resistance cases and the impact of herbicide resistant (HR) weeds. While the nature of crop production varies widely around the world, herbici...

Amaranthus tuberculatus is a troublesome weed in corn and soybean production systems in Midwestern USA, due in part to its ability to evolve multiple resistance to key herbicides including 4-hydroxyphenylpyruvate dioxygenase (HPPD). Here we have investigated the mechanism of resistance to mesotrione, an important chemical for managing broadleaf wee...

Supporting information file for whole plant dose response, qPCR, uptake, translocation and metabolism tests. (XLSX)

Oryza sativa (weedy red rice), the same species as cultivated rice, is a serious problem in rice production worldwide. Seed dormancy contributes to its persistence. We determined the effect of germination temperature and after-ripening period on germination capacity (GC) of red rice seeds from Arkansas rice fields in three production zones. We also...

Red rice (Oryza sativa L.), a weedy relative of cultivated rice (O. sativa), is a troublesome weed in rice in the southern United States. It is also very problematic in other world regions where rice is grown. There are many types of red rice. Some have white pericarp. In this paper, the term ‘red rice’ will be used to refer to the weedy types that...

Weedy rice, specifically red rice (Oryza sativa L.), is a major weed in rice which causes up to 80% yield loss and reduction of grain quality. Red rice accessions from Arkansas, U.S.A., were characterized to classify red rice accessions into certain phenotypic groups relevant to weedy rice management. The red rice accessions were 70% strawhull, 22%...

Shivrain VK, Burgos NR, Agrama HA, Lawton-Rauh A, Lu B, Sales MA, Boyett V, Gealy DR & Moldenhauer KAK (2010). Genetic diversity of weedy red rice (Oryza sativa) in Arkansas, USA. Weed Research50, 289–302. Weedy red rice (Oryza sativa) is a problematic weed in cultivated rice. About 50% of US rice is produced in Arkansas and 60% of these fields hav...

Cowpea has limited options for weed control. Hand weeding is expensive therefore herbicide options are needed to manage the weeds effectively and economically. The experiment was conducted in 2008 and 2009 at the Vegetable Research Station, Kibler, AR to evaluate the efficacy and crop safety of various herbicides when applied preplant (PP) or preem...

The effects of different herbicide treatments and maturation stage on sugar content of sweet sorghum ‗Dale' were evaluated. Sweet sorghum (Sorghum bicolor (L.) Moench) is a C 4 plant with high biomass production potential and high sugar yield. It has a shorter growing season than sugarcane hence can be grown in many geographic areas, and contains a...

Gene transfer from weeds to crops could produce weedy individuals that might impact upon the evolutionary dynamics of weedy populations, the persistence of escaped genes in agroecosystems and approaches to weed management and containment of transgenic crops. The present aim was to quantify the gene flowrate from weedy red rice to cultivated rice, a...

Red rice is a major weed problem in rice production of the southern United States and other rice-producing countries. One hundred thirty red rice accessions from 26 rice-growing counties in Arkansas were tested for tolerance to imazethapyr in seed- and whole-plant response bioassays. The red rice accessions were compared with imazethapyr-resistant...

Experiments were conducted to determine the inheritance of resistance in crosses between imazethapyr-resistant rice and red rice. Past experiments on red rice control, using the Clearfield rice technology, resulted in outcrossing between Clearfield rice and Stuttgart strawbull red rice. The F, generation of these spontaneous crosses were characteri...

Chemical options for weed control in commercial cowpea production are limited. Repeated long-term use of the acetolactate synthase (ALS) inhibitor, imazethapyr, has resulted in selection for ALS-resistant populations of Palmer amaranth. Experiments were conducted at Bixby, OK, and Kibler, AR, from 2001 to 2003 to evaluate the tolerance of cowpea cu...

The commercialization of imazethapyr-resistant (Clearfield™, CL) rice in the southern United States has raised serious concerns about gene flow to red rice, producing imazethapyr-resistant red rice populations. Our objectives were to determine the impact of planting date, CL cultivars, and red rice biotypes on outcrossing rate; and to investigate t...

The introduction of Clearfield (CL) rice cultivars resistant to imidazolinone herbicides, acetolactate synthase (ALS) inhibitors, has raised concerns of gene flow to weedy rice genotypes collectively called "red rice" that infest rice-growing areas in the southern United States. This experiment was conducted to study hybridization between CL rice a...

Cultivated rice yield losses due to red rice infestation vary by cultivar, red rice density, and duration of interference. The competition effects of red rice could be influenced further by emergence characteristics, red rice biotype, and planting time of cultivated rice. We aimed to characterize the emergence of red rice biotypes at different plan...

The transfer of the imazethapyr-resistant gene from Clearfield (CL) rice to red rice is an ecological risk. Flowering synchronization and genetic compatibility between cultivated rice and red rice could influence gene transfer. We examined the (1) variability in maximum outcrossing rate between 12 red rice biotypes and 'CL161' rice during their pea...

Two red rice accessions from Arkansas have been found to be resistant to the labeled rate of imazethapyr, which is used to control red rice in Clearfield (TM) rice. Full-length amplification of the acetolactate synthase (ALS) gene in imazethapyr-resistant red rice revealed a coding sequence of 1,935 base pairs, which is the same as that of the cult...

Imidazolinone-herbicide-resistant Clearfield™ (CL) rice allows the selective chemical control of red rice (Oryza sativa L.), a major weed problem in rice-growing areas of the southern US, using herbicides that otherwise are toxic to the crop. However, selection imposed by the herbicide of resistant individuals resulting from gene flow, and of natur...

Southernpea is a major vegetable crop in Arkansas and Oklahoma for commercial production and home gardens. Complete weed control is necessary for this crop in commercial production to keep the peas free of contaminants and achieve high harvest efficiency. Several weeds like pigweed, cocklebur, velvetleaf, lambsquarters, hophornbeam copperleaf, nigh...

Red rice is a troublesome weed in rice-growing areas of the southern U.S. Red rice in Arkansas may be diverse enough to warrant some adjustments in weed control programs. A study was conducted at the Rice Research and Extension Center (RREC), Stuttgart, Ark., in 2003 to determine the phenotypic diversity of red rice in Arkansas. One hundred thirty-...

Red rice (O. sativa L.) is a major weed problem in rice-growing areas of the southern U.S. Similar genetic make up of rice and red rice makes it difficult to control red rice with conventional herbicides. Herbicide-resistant Clearfield® (CL) rice now offers an excellent option for red rice control. This technology, however, accentuates the risk of...

Red rice and rice belong to the same genus and species. Both are self-pollinated plants, but some outcrossing has been documented. Due to outcrossing, there are chances of resistant gene transfer from herbicide-resistant rice to red rice, which may increase the weediness of red rice. In 2000 simultaneous flowering was observed be-tween Clearfield®...