However that camouflage is deceiving, and the outcome will be lack of each yield and rice high quality, mentioned Nilda Burgos, professor of weed physiology and molecular biology for the Arkansas Agricultural Experiment Station.
Burgos has been engaged on the issue of crimson rice for a few years. However now, she mentioned, she has to think about it by way of various shades of weedy rice. “It’s not simply crimson rice, anymore.”
The problem is that crimson rice is identical genus and species as cultivated rice, Burgos mentioned. That results in “gene stream,” when cultivated rice cross-pollinates with the weeds that survive from one yr to the following. An issue could not manifest after a single rice season, however after repeated years of “fraternization” between weedy and home rice, the weeds current issues.
Burgos mentioned she didn’t anticipate finding an enormous downside with crimson rice at first as a result of rice is
self-pollinating. That slows the speed of cross-pollination, particularly for the reason that reproductive
window of particular person varieties is comparatively slim.
“However we discovered that issues start to occur after a number of seasons,” Burgos mentioned, “particularly in fields the place hybrids have been rising for a few years.”
Rice grains that fall out and are left within the subject will develop up volunteers in following years.
Outcrossing with weedy rice leads to quite a few offspring that manifest many hues of off-color rice, and ranging maturity dates. This results in a wider window for cross-pollination, which results in extra types of weedy rice.
“The volunteers are bridges for outcrossing with weedy rice,” Burgos mentioned.
As a result of weedy rice typically matures later than standard varieties, its improvement is usually stunted earlier than grain maturity when cooler climate comes on within the fall. “Second or third generations of weedy rice outcrosses solely exist when it stays heat,” Burgos mentioned.
That makes weedy rice an even bigger downside in nations with tropical climates, Burgos mentioned. However it’s additionally an issue as heat climate stretches longer into fall within the U.S.
“In the case of world warming, weeds are going to adore it,” Burgos mentioned. “Outcrossing and herbicide resistance will develop into worse.”
The rise of weedy rice isn’t anybody’s fault, she mentioned. “It’s a mix of things, together with crops, climate, local weather, economics, obtainable agricultural expertise, obtainable data and farming practices.”
Hybrids have handed alongside herbicide resistance to weedy rice, Burgos mentioned.
“Hybrid rice is extra appropriate with crimson rice and the outcrossing fee is greater,” Burgos mentioned. “The outcrossing fee in hybrids is double that of standard rice varieties.” That’s nonetheless low, due to rice being self-pollinating, Burgos mentioned. However it implies that it takes
fewer seasonal cycles earlier than issues start to mount up.
In addition to inflicting complications for weed management, the various hues of weedy rice mar the constant white coloration desired on the rice mills, Burgos mentioned. That causes devaluation of the crop, and a reduced value paid to the farmers.
Being the identical species as cultivated rice implies that weedy rice can also be competing with the crop for sources all through the rising season, robbing the crop of vitamins and water, Burgos mentioned.
The variability in maturity date additionally means the weedy rice could also be overly mature or
under-mature at harvest. Grains from overly mature weedy rice shatter within the subject, leaving seed that may develop up as weeds within the following season, or throughout milling, damaging a crop’s milling yield.
Underneath-mature weedy rice at harvest means moisture content material might be too excessive, complicating rice drying.
Plant top of weedy rice is constant within the first era, Burgos mentioned. However it begins to range in succeeding generations.
With all this happening, Burgos mentioned, weedy rice wreaks havoc within the rice subject. Burgos quantified yield loss for various varieties and rising situations. The weeds additionally lead to decrease rice high quality and, in worst instances, can severely injury the entire crop.
Avoiding injury from weedy rice begins with zero tolerance weed administration, Burgos mentioned. “Don’t depart something in your subject. And don’t neglect the perimeters of the fields.”
Many growers clear up their fields completely, however neglect the perimeters and ditches, Burgos mentioned. The next yr, weedy rice sprouts up on the peripheries of rice fields and spreads in from the perimeters.
Additionally, weedy rice seed that drops in water within the ditches will get carried to different areas and may sprout up anyplace.
Rotating hybrid rice with standard varieties may also sluggish gene stream and inhibit improvement of herbicide resistant weeds, Burgos mentioned. Rotating rice with different crops, like soybeans, and the totally different weed management methods used with these crops may help hold rice fields clear. She additionally advises rotating weed management methods.
“Ensure that, no matter you employ, you allow no weedy rice within the subject,” Burgos mentioned.
“Farmers are seeing extra resistant weedy rice,” Burgos mentioned. “Any subject that has had Clearfield in it for a few years might be extra more likely to see it.”
Burgos is making ready an article based mostly on a survey of weedy rice in Arkansas, which might be revealed by the Division of Agriculture.