Neglecting Rice Milling Yield and Quality Underestimates Economic Losses from High-Temperature Stress

Lyman, Nathaniel; Jagadish, Krishna S.V.; Nalley, Lawton Lanier; Dixon, Bruce L.; Siebenmorgen, T. J.

doi:10.1371/journal.pone.0072157

Cited by 203 publications

(150 citation statements)

References 33 publications

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“…Grain breakage is a well-known feature of rice milling 19,20 . However, it is as yet unknown which end of the grain is more likely to be broken off, or how this may be influenced by genotype and environment.…”

Section: Discussionmentioning

confidence: 99%

Iron and zinc variation along the grain length of different Thai rice varieties

Laenoi¹,

Prom‐u‐thai²,

Dell³

et al. 2015

ScienceAsia

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This study examined the distribution of iron (Fe) and zinc (Zn) along the grain length of seven rice varieties. The experiment was conducted in a completely randomized design with two factors (variety and grain fraction) and three independent replications. Samples of brown and white rice of six common Thai rice varieties and a high Fe and Zn variety, IR68144, were transversely cut into three fractions per grain (basal, middle, and distal) with approximately the same length in each fraction. The concentration of Fe and Zn was determined by the dry ashing method and quantified using atomic absorption spectrometry. The middle grain fraction of brown rice was found to have the lowest Fe and Zn with greater concentration of Fe and Zn in the basal (embryo end) than the other fractions. The rice varieties differed in the amount of Fe and Zn allocated to different fractions of the endosperm (white rice). The potential for loss of Fe and Zn during milling due to their uneven distribution along the grain length will become more significant when higher nutrient concentrations are involved, such as those achieved by biofortification efforts. Micronutrient distribution needs to be taken into consideration to ensure that rice consumers benefit from Fe and Zn biofortification.

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Section: Discussionmentioning

confidence: 99%

Iron and zinc variation along the grain length of different Thai rice varieties

Laenoi¹,

Prom‐u‐thai²,

Dell³

et al. 2015

ScienceAsia

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“…High-temperature stress during the grain filling stage can decrease the quantity of paddy rice available for milling and, more importantly for this study, affect the HRY. More specifically, high temperatures have been shown to decrease the quantity of kernel head rice and to increase the quantity of broken kernels (Counce et al, 2005;Cooper et al, 2008;Lyman et al, 2013). Counce et al (2005) and Cooper et al (2008) found that high nighttime temperatures during the grain-filling stage lead to disruptions in the enzymatic activities that are responsible for kernel filling, which in effect could produce chalkiness and thereby lessen average kernel strengths as well as lower HRY.…”

Section: Optimal Harvest Moisture Content For Maximizing Mid-south Rimentioning

confidence: 99%

“…In addition to HMC, HRY is hypothesized to be a function of weather variables, which have been shown to affect HRY (Lyman et al, 2013;Counce et al, 2005;Cooper et al, 2008). By omitting factors that are correlated with both HRY and HMC (e.g., weather), the coefficient estimates of HMC are biased due to specification error (Greene, 2012).…”

Section: Statistical Analysis Estimating Head Rice and Milled Rice Yimentioning

confidence: 99%

“…Following Cesaraccio et al (2001), daily minimum and maximum temperatures were used to estimate a sinusoidal distribution of exposure to each 1°C interval, as Schlenker and Roberts (2009) suggest. A nighttime temperature of 22°C was used as the stress threshold, in keeping with the established literature on the critical heat-stress temperatures for rice (Lyman et al, 2013;Tack et al, 2014) W1]) and grain-filling (postheading or Window 2 [W2]). Window 1 is defined as emergence until 50% heading, and W2 is defined as 50% heading to harvest.…”

Section: Statistical Analysis Estimating Head Rice and Milled Rice Yimentioning

confidence: 99%

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Optimal Harvest Moisture Content for Maximizing Mid‐South Rice Milling Yields and Returns

et al. 2016

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A gronomy J our n al • Volume 10 8 , I ssue 2 • 2 016 701 R ice (Oryza sativa L.) is unique from other major row crops in the United States in that it requires postharvest milling before pricing. As a result, profi tability is based on both mass yield and kernel integrity. Broken rice (also called "brokens"), which is typically either ground into fl our or used in pet food, is currently valued at 68.5% of unbroken kernels, or head rice yield (HRY) (USDA-FAS, 2014). Studies have shown that although kernels of some rice cultivars are genetically more susceptible to breakage during milling, the rice moisture content (MC) at the time of harvest (HMC) and exposure to high nighttime air temperatures during critical stages of production can directly aff ect the ratio of unbroken rice (i.e., HRY) to broken rice on milling.Other studies indicate that fi ssures in the kernel will develop when rice at low MC (£15%) is exposed to conditions that cause the dry rice kernels to rapidly absorb moisture (Kunze and Prasad, 1978;Siebenmorgen and Jindal, 1986). Subsequently, fi ssures form within the rice kernel when internal stressors exceed the material tensile strength of the kernel. Th ese fi ssures are fault lines where the kernel breaks during milling, which in eff ect reduces the number of intact kernels and increases the associated number of brokens. Similarly, harvesting rice at a high MC (>22% for long-grain cultivars) also creates a large proportion of broken kernels as a result of milling a greater number of immature kernels (Siebenmorgen and Qin, 2005;Siebenmorgen et al., 2006;Bautista et al., 2007). Th ese immature kernels are typically thinner, weaker, and more susceptible to breakage during milling than fully mature kernels; thus, there is a convex relationship between HRY and HMC. Furthermore, Siebenmorgen et al. (2007) found that each rice cultivar and type (long grain, medium grain, and short grain) has a diff erent optimal HRY and MC that maximizes the HRY. Siebenmorgen et al. (1992) showed that signifi cant losses in HRY arise when long-grain rice in Arkansas is harvested at MCs <15% or >22%. However, maximizing HRY is not necessarily a profi t-boosting strategy because drying costs are a necessary component of profi tability, with the charges depending on the ABSTRACTRice (Oryza sativa L.) is unique from other major row crops in the United States in that it requires postharvest milling before pricing. As a result, profi tability is based on mass yield (paddy yield) and kernel integrity, or head rice yield (HRY). A common dilemma rice producers confront is the selection of a harvest moisture content (HMC) to begin harvesting. Although harvesting with a high HMC can improve HRY, it also increases drying costs at the mill. Conversely, harvesting with a low HMC can save in drying costs but decreases HRY due to fi ssuring. Th is study determines the optimal harvest HMC that maximizes net value, accounting for both HRY and drying costs per megagram of rice, considering genetic diff erences across cultivars and th...

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“…The problem is within the context of the supply chain, there is some innate friction that exists between market participants who prefer smooth price fluctuations and financial market investors who profit from wide price fluctuations in the commodities that they invest in. Consequently, rice producers, for instance focus on reducing the uncertainly in commodity prices because they need to make long-term planting decisions, labor investments and production agreements that are primarily risk averse factors (Lyman, Jagadish, Nalley, Dixon, & Siebenmorgen, 2013). It is apparent that price volatility in the downstream supply channel can greatly disrupt profitability for food commodities producers.…”

Section: Price Volatility Of Food Commoditiesmentioning

confidence: 99%

Supply Chain Disruptions and Their Effect on Volatility of Rice Prices in Saudi Arabia

Fayad¹

2016

IJMS

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This research has examined the issue of supply chain disruptions and how they affect price volatility in the commodities marketplace. Specifically, this point was discussed and examined in relation to the rice imports undertaken by Saudi Arabia with respect to how supply chain disruptions in the rice supply channel contributes to price volatility. The supply chain was first identified to consist of various nodes along which market participants work to move the commodity from one point to another. The observation was confirmed that any disruptions up the supply chain tended to manifest themselves in downstream effects such as the bullwhip effect in which increased inventory levels or decreasing inventory levels are felt successively further down the supply chain. These and factors relating to supply as well as demand in other markets also were identified to contribute to price volatility for Saudi Arabia and its rice imports. The analysis demonstrated that every major global economic disturbance over the past 50 years corresponded to fluctuations in the price of food commodities. Saudi Arabia was shown to receive the vast majority of rice supplies from a single market which is India. India supplies Saudi Arabia with some 72% of its rice imports which ensures that any transportation or customs issue encountered by any supply channel participant prior to the Kingdom's receipt of its rice will alter the price profile of these rice commodities. Saudi Arabia was shown to already have experienced substantial price volatility of its rice imports with much of this volatility originating in India due to suppliers in India responding to competing demand for its Basmati varieties of rice. This volatility was manifested during 2012 and 2013 when rice prices per metric ton increased some 40% overall. Finally, this report also undertook regression analysis of the rice import data that found positive correlations between variables such as time between harvest and distribution, milling facility ownership and road/shipping lane conditions and the price structure of rice. The conclusion is that supply chain disruptions can and periodically do result in price volatility for rice in Saudi Arabia. Hence, this report finds that certain factors such as information access, the establishment of long-term contracts as well as trade group membership can be effective at reducing the transaction costs in the Kingdom's rice market. Essentially, these factors can work to place downward pressure on rice prices by the metric ton which would flatten out some of the price volatility in Saudi Arabia's rice imports.

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Neglecting Rice Milling Yield and Quality Underestimates Economic Losses from High-Temperature Stress

Cited by 203 publications

References 33 publications

Iron and zinc variation along the grain length of different Thai rice varieties

Iron and zinc variation along the grain length of different Thai rice varieties

Optimal Harvest Moisture Content for Maximizing Mid‐South Rice Milling Yields and Returns

Supply Chain Disruptions and Their Effect on Volatility of Rice Prices in Saudi Arabia

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