Conventional Maize Research Articles

Review on Maize (Zea mays L.) Breeding Methods for Improving Quality Protein and Others Nutritional Traits Lemi Yadesa

Maize (Zea mays L.) is a member of the grass family Gramineae (Poaceae) and one of the oldest cultivated crops. To date, maize is widely cultivated in most parts of the world, over a wide range of environmental variables signifying its global and regional importance to millions of people who rely on the crop in pursuit of food security and livelihoods. Now a days, maize mixed with tef is also widely used in towns for making injera. To alleviate malnutrition, protein content can be increased to as high as 18% by increasing the prolamine (zein) fraction in maize endosperm, but unfortunately it consequently led to lysine and tryptophan deficiency. Since maize is a primary crop in the majority of farming systems and staple food of the rural population in much of the mid-altitude sub- humid agro-ecologies of Ethiopia, substituting the conventional maize (CM) with quality protein maize (QPM) can substantially improve the protein status and greatly reduce the malnutrition problem of resource-poor farmers and low-income people that depend on maize as their staple food. Recent evidence indicates that protein and amino acids play biological roles in protein and lipid synthesis, bone elongation, and the regulation of these and other processes necessary for linear growth. The intensities of lysine or tryptophan should be constantly restrained during the breeding process to sustain the protein quality in grain even when the op2op2 genotype is preserved. The maize kernel, like that of other cereal grains, includes pericarp (6%), endosperm (82%) and germ (12%).Molecular marker-assisted selection, often simply referred to as marker-assisted selection (MAS) offers such a possibility by adopting a wide range of novel approaches to improving the selection strategies in horticultural crop breeding. Appreciative concrete achievements in improving nutritional quality of food crops through conventional breeding efforts necessitate long-term investments, sustained research efforts and patience, besides continuing administrative, financial and scientific support. Further extensive use of MAS is also predictable with the enhancement of methods for marker analysis and identification of applicant genes for commercial traits. Appreciative concrete achievements in improving nutritional quality of food crops through conventional breeding efforts necessitate long-term investments, sustained research efforts and patience, besides continuing administrative, financial and scientific support. Time savings will be attained through MAS may be as significant as cost savings where there are reasonable markets for developed cultivars. DOI: 10.7176/JBAH/11-21-02 Publication date: November 30 th 2021

Subsoiling and conversion to conservation tillage enriched nitrogen cycling bacterial communities in sandy soils under long-term maize monoculture

Desertification degrades soil health and severely reduces crop productivity. Conventional tillage practices can amplify these problems in arid and semi-arid regions. For semi-arid regions in Inner Mongolia, China, the effects of introducing different tillage practices such as subsoiling (SS), straw mulching (SM), and no-tillage (NT) on otherwise long-term conventional tilled maize monoculture systems, were examined in the context of sandy soil bacterial and archaeal community diversity. Results showed that after three to four years of introduction, subsoiling and conversion to conservation tillage practices had no immediate effect on the alpha-diversity of the soil microbial communities. The beta-diversity of the soil microbial communities was less affected by the introduced tillage practices than by the growing season conditions, soil moisture, total nitrogen, soil macro-aggregate, and organic matter. Importantly, the introduced tillage practices had a notable effect on soil microbial communities associated with nitrogen (N) cycling processes, especially N fixation, nitrate reduction, nitrification, and denitrification. In particular, several years of tillage change from long-term conventional tillage enhanced the abundance of KEGG orthologs (KOs) associated with N fixation function involving species in Rhodoplanes, Nitrospira, Skermanella, and Rhizobium according to PICURSt prediction. Rhodoplanes spp. are involved in nitrate reduction and denitrification processes, and Nitrospira spp. associated with nitrite oxidization. We conclude that, for maize monoculture systems in semi-arid sandy soils, the soil bacterial and archaeal communities associated with many beneficial N cycling processes can be significantly impacted by only three to four years of introduced conservation and subsoiling tillage practices.

English

Maize (Zea mays L.) is the most important cereal crop on which many smallholder farmers in sub-Sahara Africa (SSA) depend on as a sole source of calories, proteins, and vitamins. However, conventional maize is deficient in two essential amino acids, lysine, and tryptophan. Thereafter, Quality Protein Maize (QPM) developed to combat protein malnutrition. In SSA low soil nitrogen is also the most limiting factor in maize production and productivity. To determine the combining ability of QPM inbred lines for grain yield and other agronomic traits under low and optimum N environments, 121 genotypes generated using 11 QPM inbred lines in a complete diallel mating design with 5 checks were evaluated under both low and optimum N environments at 3 locations in the 2018 cropping season. Significant differences were observed among the genotypes for major characters under both low and optimum N environments. Under low and optimum N environments, non-additive gene actions were more important than additive gene action for grain yield, number of ears per plant, plant and ear height, ear length and diameter. Under low N environments, more contributions of reciprocal effects than GCA effects were observed for number of ears per plant, plant aspect, ear diameter. Parental lines TL156579, TL156583, and TL148288 were considered as a good general combiner for grain yield under low N environments. Parental line TL156612 showed higher positive GCA effects when used as female while parental line TL156612 showed higher negative GCA effects when used as a male parent for grain yield under low N environments.   Key words: Complete diallel, general combining ability, low soil nitrogen, lysine, optimum soil nitrogen, quality Protein maize, reciprocal effect, tryptophan.

Addressing the challenges of non-target feeding studies with genetically engineered plant material – stacked Bt maize and Daphnia magna

Previous studies reported adverse effects of genetically engineered maize that produces insecticidal Cry proteins from Bacillus thuringiensis (Bt) on the water flea Daphnia magna. In the current study, effects of flour, leaves, or pollen from stacked Bt maize that contains six Bt proteins (SmartStax) in two plant backgrounds on life table parameters of D. magna were investigated. Adverse effects were observed for Bt maize flour, originating from different production fields and years, but not for leaves or pollen, produced from plants grown concurrently in a glasshouse. Because leaves contained eight to ten times more Cry protein than flour, the effects of the flour were probably not caused by the Cry proteins, but by compositional differences between the plant backgrounds. Furthermore, considering the natural range of variation in the response of D. magna to conventional maize lines, the observed effects of Bt maize flour were unlikely to be of biological relevance. Our study demonstrates how Cry protein effects can be separated from plant background effects in non-target studies using Bt plant material as the test substance and how detected effects can be judged for their biological relevance.

The distribution of phosphorus, carotenoids and tocochromanols in grains of four Chinese maize (Zea mays L.) varieties

Grains of three specialty maize varieties and one conventional maize variety cultivated in China were collected and dissected to obtain the germ, endosperm, and pericarp fraction, and the distribution pattern of phosphorus, carotenoids, and tocochromanols was determined. The results showed that phytochemical contents varied significantly among different maize fractions. The germ fraction accounted for 78.3 to 86.5% of the total phosphorus present in the maize kernels. Over 86.9% of carotenoids were located in the endosperm. Except for waxy maize, 64.5 to 74.8% of the tocochromanols were contributed by the germ. Considerable differences in phytochemical contents were observed between the genotypes. Waxy maize contained the highest content of tocopherols, tocotrienols and tocochromanols meanwhile waxy maize had the lowest carotenoid and phytate phosphorus content. High lysine maize contained the highest levels in carotenoids and lowest tocochromanols. Over all, total carotenoids were significantly inversely associated with total tocochromanols.

Baby corn production and utilization of remaining fodder in total mixed ration of buffalo calves

This study was taken up to find out suitable maize variety cultivated with or without fertilizer for baby corn ear production and evaluation of leftover fodder/green stalks as livestock feed. Experiment-1: Six varieties of hybrid maize [PMH-1 grain (V1), Bulland (V2), African Tall (V4), Dekalb 7074 Monsanto (V5), Proagro 4640 (V6), Egyptian variety G-5414 (V7)] and one composite maize variety J1006 (V3) were cultivated without fertilizer (F1), with either Azotobacter treated seed (F2), recommended dose of fertilizer (F3), or F2 + F3 (F4) at the University Farm. Experiment-2: The leftover fodder of the best baby corn hybrid variety and that from V3 were evaluated in total mixed ration (TMR) as feed for buffalo calves. In Experiment-1 the weight of edible cob without husk and fodder yield were the highest (P<0.01) in V2. The in vitro net gas production, digestibility of nutrients and ME availability from the fodder was the highest in V7 comparable to V2, but higher than other varieties. The fodder from baby corn G-5414 was considered as the best. In Experiment-2 the chemical composition and in vitro evaluation of TMRs containing either conventional maize fodder (TMR-1; J-1006) or baby corn fodder (TMR-2; Baby corn G-5414) were comparable. Both the TMRs were iso-nitrogenous and iso-caloric. The digestibility of proximate and a cell wall constituent was considerably higher in calves fed TMR-2 than those fed TMR-1. The efficiency of nitrogen utilization, blood profile and excretion of purine derivatives in the urine were comparable in both groups. It was concluded that fresh baby corn fodder can be utilized efficiently by the ruminants without any adverse effect on the health of animals.

Suitability of Hybrid and Landrace Maize Plants Within Conventional and Organic-Polyculture Maize Agroecosystems for Hosting Parasitic Wasps

Abstract Polycultures and conventional monoculture have different effects on insect pests and natural enemies. Little is known about the parasitoid response to landrace and hybrid plants damaged by insect pests within organic-polyculture agroecosystems vs. monoculture ones. The aim of the present study was to compare the suitability of these agroecosystems for hosting parasitic wasps by evaluating the parasitism rate, parasitoid abundance, and species composition on landrace and hybrid maize races within organic-polyculture and conventional maize agroecosystems. This study was performed within the Mesoamerican region where maize was originally domesticated and where the maize insect pest Dalbulus maidis (DeLong) (Hemiptera: Cicadellidae) originated. Maize plants of landrace and hybrid varieties were used to attract egg parasitoids of D. maidis within each of the two agroecosystems; conventional maize monoculture and an organic-polyculture of landrace maize, beans, and squash, which also included weed plants. Four treatments were conducted in this field experiment: 1) landrace-within organic agroecosystem, 2) hybrid-within organic agroecosystem, 3) landrace-within conventional agroecosystem, and 4) hybrid-within conventional agroecosystem. A community of parasitic wasps, of which the micro-wasp Paracentrobia sp. (Hymenoptera: Trichogrammatidae) was the most abundant member, was found attacking the D. maidis eggs in both agroecosystems. The parasitism rate and parasitoid abundance were similar among the four treatments. However, the abundance of parasitoids was greater in the conventional maize monoculture. Bait plants (landrace and hybrid maize) within each agroecosystem did not show differences in either parasitoid abundance or parasitism rate.

Effects of conventional versus no-tillage systems on the population dynamics of elaterid pests and the associated damage at establishment of maize crops

No-till agriculture, combined with the practices of continuous soil cover by retaining crop residues and of crop rotation, including cover crops, represents a relatively widely adopted management system that aims to increase soil organic matter content as well as long-term sustainability. However, its impacts on wireworm populations in the soil and risk of damage to crops are uncertain, and current recommendations may unjustifiably limit grower options. Consequently, this study examined the effects of no-tillage soil management on the population dynamics of Agriotes wireworm pests (Coleoptera: Elateridae) by bait sampling, maize plant damage assessments, and pheromone trapping (adults) within three farms in northeastern Italy, from 2011 through 2016, as compared to conventional tillage. The four-year cropping rotation consisted of winter wheat (Triticum aestivum), oilseed rape (Brassica napus), maize (Zea mays), and soybean (Glycine max) under both tillage treatments. The nature and intensity of damage caused by wireworms to maize early stages was assessed each year. Wireworms and beetles comprised of four different species (A. brevis, A. sordidus, A. ustulatus, and A. litigiosus) were captured, with the numerically dominant species (A. sordidus) accounting for over 90% of all captures. All species responded similarly to tillage practices. No effects of tillage operations were associated with beetle captures (P > 0.28) and larval densities (P > 0.45). No differences were observed between tillage treatments in wireworm feeding maize damage scores (P > 0.17; means for no-till and conventional tillage maize were 3.82 and 4.14 percent damage, respectively). These results suggest that switching from a conventional tillage system to a no-till maize production may not cause an increase of wireworm damage to maize, even though no-till conditions have been historically associated with increased wireworm damage risk. Possible causes of these results are discussed.

Arthropod fauna associated with organic and conventional maize crop

The corn crop has a marked sensitivity to biotic and abiotic stresses. As a control method, basically, transgenic plants have been used in association with chemical control. However, frequent applications of insecticides affect the conservation of biodiversity, and consequently, the natural regulation of insect populations. Thus, the objective of the work was to compare the diversity of arthropodofauna associated with the cultivation of corn in organic and conventional systems. The experiments were carried out at Fazenda Nossa Senhora Aparecida, in Hidrolândia/GO, in two areas: one in a consolidated organic system and the other in a conventional system. The organic area (1 ha) was sown with the Creole variety Palha Roxa and no type of cultural treatment was carried out. The conventional area (10 ha) was sown with a transgenic hybrid resistant to the herbicide glyphosate 30F53VYHR and two chemical fertilizers were applied, for planting and cover, two applications of herbicides and an application of insecticide. To survey the arthropodofauna, in each area, two collections were made with six pitfall soil traps. The first collection was carried out in the vegetative stage and the second in the reproductive stage, approximately at 35 and 80 days after planting, respectively. The traps were kept in the field for a week. In addition, a collection with entomological net was carried out in 10 plants chosen at random. The collected insects were stored in plastic pots containing 70% alcohol and taken to the laboratory for quantification and identification. The data referring to the total of insects collected were submitted to the T test at 5% probability. In the two collected with pitfall traps, the largest number of arthropods was collected in the area of ​​organic cultivation, with greater diversity of orders and families in this area. In the collection performed with entomological network, there was no difference between the places of cultivation. Organic crops provide better conditions for establishment and development for insects, especially those that spend some life in the soil. Therefore, the diversity of arthropods is greater in this cultivation system.

Effects of legume intercropping and nitrogen input on net greenhouse gas balances, intensity, carbon footprint and crop productivity in sweet maize cropland in South China

How to achieve greater crop productivity with lower greenhouse gas (GHG) emissions from limited farmland has been a hotspot of interest in global agricultural production. In this study, we analyzed the effects of legume intercropping and nitrogen (N) fertilizer level on net greenhouse gas balances (NGHGB), yield-based greenhouse gas emissions intensity (GHGI), carbon footprint (CF) and crop productivity in sweet maize cropland in South China based on a long-term field experiment during 2013–2018. Results demonstrated that the sweet maize/soybean intercropping pattern could improve crop productivity on the unit of arable land, but the yield advantage of the intercropping system was totally derived from the soybean. Accordingly, the intercropping pattern reduced the GHGI with significant difference compared to the sweet maize mono-cropping system. Therein, the difference between the sweet maize/soybean intercropping with crop line ratios of 2:3 (S2B3) and 2:4 (S2B4) were not significant. Furthermore, suitable N input during the sweet maize cultivation in the region were necessary for improving the crop productivity and decreasing the GHGs emission in farmland. Also, the difference of N levels was significant to the GHGs emissions, soil organic carbon sequestration, GHGI and NGHGB. The 300 kg N ha−1 showed the better effect for lowering the NGHGB and CF in sweet maize farmland when keeping crop productivity. The interaction effect of the N level and crop pattern just showed on the crop yields and GHGI. The S2B4 with 300 kg N ha−1 showed significant benefits with respect to maintaining the yields and reducing the net GHGs emissions compared to conventional sweet maize farming system in the Pearl River Delta in China. These advanced agricultural practices contributed to the development of clean agricultural production in China.

Small-scale traditional maize farming fosters greater arthropod diversity value than conventional maize farming

Globally insects are in decline, with the transformation of natural areas for agriculture one of the most important drivers of this decline. Yet, insects play an important role in regulating ecosystem services such as pollination, soil fertility and pest suppression, so their conservation within agricultural areas is critical. We examined comparative impacts of traditional small-scale low input farming versus large-scale conventional farming systems, and mono-cropped versus inter-cropped systems in Kenyan maize fields on predator, ant and herbivore arthropod species richness and composition. We also considered the value of hedgerows and percentage of surrounding maize cover for arthropod conservation. As expected, traditional farming retained higher herbivore species richness, evenness and abundance, as well as higher predator abundance compared to conventional farming. Percentage maize cover was positively correlated to ant species richness, predator and herbivore abundance, as well as determining species assemblage composition for ants and herbivores. Hedgerow volume and the comparison of mono- vs inter-cropping were important predictors for predator evenness. These results suggest that the low input farming systems retain far higher arthropod numbers, although this does not seem to be due to the use of intercropping on the farms. Rather it seems that hedgerows play an important role in maintaining arthropods. While higher maize coverage surrounding the farm increases the species and abundance of arthropods in the fields, this is most likely due to the high biotope fidelity of arthropods that specialize in open cropping systems such as maize fields.Implications for insect conservationThe results here are encouraging as the retention of culturally important farming techniques (i.e., the traditional Kenyan farmers) and small improvements, such as the retention of hedgerows, greatly promotes biodiversity in the farmlands.

Economic and ecosystem impacts of GM maize in South Africa

White maize in South Africa is the only staple crop produced on a widespread commercial basis for direct human consumption using genetically modified (GM) cultivars. Using a combined economic and environmental approach, we estimate the total welfare benefits attributable to GM white maize in South Africa for 2001–2018 are $694.7 million. Food security benefits attributable to GM white maize in South Africa also manifest through an average of 4.6 million additional white maize rations annually. To achieve these additional annual rations using conventional hybrid maize, the additional land required would range from 1088 ha in 2001 to 217,788 ha in 2014. Results indicate that GM maize reduces environmental damage by $0.34 per hectare or $291,721 annually, compared to conventional hybrid white maize.

Biofortified and fortified maize consumption reduces prevalence of low milk retinol, but does not increase vitamin A stores of breastfeeding Zambian infants with adequate reserves: a randomized controlled trial

Replacement of conventional staples with biofortified or industrially fortified staples in household diets may increase maternal breast milk retinol content and vitamin A intakes from complementary foods, improving infant total body stores (TBS) of vitamin A. To determine whether biofortified or industrially fortified maize consumption by Zambian women and their breastfeeding infants could improve milk retinol concentration and infant TBS. We randomly assigned 255 lactating women and their 9-mo-old infants to a 90-d intervention providing 0 µg retinol equivalents (RE)/d as conventional maize or ∼315 µg RE/d to mothers and ∼55 µg RE/d to infants as provitamin A carotenoid-biofortified maize or retinyl palmitate-fortified maize. Outcomes were TBS, measured by retinol isotope dilution in infants (primary), and breast milk retinol, measured by HPLC in women (secondary). The intervention groups were comparable at baseline. Loss to follow-up was 10% (n=230 mother-infant pairs). Women consumed 92% of the intended 287 g/d and infants consumed 82% of the intended 50 g/d maize. The baseline geometric mean (GM) milk retinol concentration was 1.57 μmol/L (95% CI: 1.45, 1.69 μmol/L), and 24% of women had milk retinol<1.05 μmol/L. While mean milk retinol did not change in the biofortified arm (β: 0.11; 95% CI: -0.02, 0.24), the intervention reduced low milk retinol (RR:0.42; 95% CI: 0.21, 0.85). Fortified maize increased mean milk retinol (β: 0.17; 95% CI: 0.04, 0.30) and reduced the prevalence of low milk retinol (RR:0.46; 95% CI: 0.25, 0.82). The baseline GM TBS was 178 μmol (95% CI: 166, 191 μmol). This increased by 24 µmol (± 136) over the 90-d intervention period, irrespective of treatment group. Both biofortified and fortified maize consumption improved milk retinol concentration. This did not translate into greater infant TBS, most likely due to adequate TBS at baseline. This trial was registered at clinicaltrials.gov as NCT02804490.

Estimation of Heterosis and Combining Ability for Yield, Yield Component Using Line × Tester Methods in Maize (Zea Mays L.)

This study was initiated with the objective of estimating heterosis, combing ability of selected conventional maize genotypes, comparison between hybrids, parents, and testers. Ten maize genotypes were selected (three testers and seven lines). The crosses were done in a Line × Tester mating design to produce 21 F1 single spring hybrids during 2018. The experiment was conducted. At fall season 2019; thirty-one genotypes (21 crosses + 3 tester + 7 lines) were sown in Randomized Complete Block design (RCBD) with three replications at Gerdarash research station/College of Agricultural Engineering Sciences, Salahaddin University, Erbil. The analysis of variance confirmed that the mean squares due to genotypes were highly significant for all studied characters, the tester parent (Talar) showed maximum value for tasseling number, while the parent Mst4279 recorded the maximum value for no. of days to 50% tasseling and silking and no. of ears/plant. The hybrid 232Dss × Talar showed maximum positive heterosis for plant height and ear length. The general combining ability variance was higher than specific combining ability for the plant height, ear height, 300 grain weight (g) and tassel branch number. These characters were identified to be under the control of additive-gene. Generally, the superior maize F1 hybrid L1×T2 is recommended to be taken to large-scale multilocational trials prior to commercial cultivation in Kurdistan region.

Exploring climate change adaptation strategies in maize (Zea mays) postharvest management practices among smallholder farmers

Climate change has negative effects on postharvest management of cereals. However, much emphasis is placed on climate change adaptation (CCA) in crop production whilst not adequately addressing the CCA in postharvest management of maize. A cross-sectional survey was conducted among smallholder farmers. Key informant interviews, observations and structured interviews on 280 household heads were done. Binary logistic regression was used to analyse determinants of use of postharvest CCA practices whilst multinomial logistic regression was used to analyse determinants of use of postharvest storage facilities. Farmers used grain protectants (40.4%) and minimised the duration of the harvesting process (34.3%) as their major CCA practices in maize postharvest management. There was a significant difference in postharvest maize loss quantities ( p ≤ 0.05) between users and non-users of CCA practices. The choice and use of climate-resilient postharvest strategies were significantly influenced by location, cultivated land, access to radio and membership to farmer club. Choice of a postharvest storage facility was significantly influenced by training and membership to farmers’ club. Smallholder farmers are using some conventional maize postharvest management practices like grain protectants to adapt to the effects of climate change. The use of maize postharvest CCA strategies significantly reduced postharvest losses.

Food/Feed and Environmental Risk Assessment of Herbicide-tolerant and Insect-resistant Genetically Modified Maize NK603 x MON810 for Import, Processing, Food and Feed Uses under Regulation (EC) No 1829/2003 (EFSA/GMO/UK/2004/01)

Food/Feed and Environmental Risk Assessment of Herbicide-tolerant and Insect-resistant Genetically Modified Maize NK603 x MON810 for Import, Processing, Food and Feed Uses under Regulation (EC) No 1829/2003 (EFSA/GMO/UK/2004/01)

Cropping system design can improve nitrogen use efficiency in intensively managed agriculture.

New agronomic and management approaches are urgently required to meet the challenges of improving resource use efficiency and crop yields in intensive agricultural systems. Here we report the fertilizer N use efficiency (FNUE), fate of fertilizer N and N budgets in newly designed cropping systems as compared with conventional winter wheat-summer maize double cropping (Con. W/M) in the North China Plain. A15N labelling approach was used to quantify FNUE by these new cropping systems which included optimized winter wheat-summer maize (Opt. W/M) with two harvests in one year; winter wheat/summer maize-spring maize (W/M-M) and winter wheat/summer soybean-spring maize (W/S-M) with three harvests in two years, and spring maize (M) with one harvest in one year. The results showed that only 18-20% of fertilizer N was recovered by crops in Con. W/M. Although Opt. W/M significantly increased FNUE to 33%-35% with increased crop yields, it consumed as much groundwater as Con. W/M. The W/M-M, W/S-M and M significantly increased FNUE to 27%-44% and reduced groundwater use and fertilizer N losses when compared to Con. W/M. The W/M-M achieved a comparable grain yield, but W/S-M and M had significantly lower grain yields when compared to Con. W/M. However, grain N harvest in W/S-M was comparable with Con. W/M due to higher grain N content in soybean. Post-anthesis fertilizer N uptake provided little contribution to total N uptake, and accounted for 5%, 12%, 7% and 2% of the average N uptake for winter wheat, spring maize, summer maize and summer soybean, respectively. When taking the second crop into account, Con. W/M recovered 27% of fertilizer N, while it increased to 36%-50% under the new cropping systems. We conclude that W/M-M and W/S-M will deliver significant improvements in the environmental footprints and sustainability of intensively managed cropping systems in the North China Plain.

Obtention and characterization of resistant starch from creole faba bean (Vicia faba L. creole) as a promising functional ingredient

A procedure easy to upscale industrially aimed at obtaining resistant starch (RS) type III (RS-III) was optimized, using a native faba bean from Mexico (Vicia faba L. creole) as RS source for the first time. Pullulanase debranching treatment (6–18 enzyme units (U)/g starch; 0–27 h) and retrogradation process (−30 °C, 2 °C or 20 °C; 1–6 days) was optimized for faba beans. Optimal conditions were determined at 18 U/g for 27 h and a retrogradation process at 20 °C for 6 days. Obtained faba bean RS was also compared with RS obtained from conventional sources, beans (Phaseolus vulgaris L. Jamapa) and maize, under these optimal conditions. Beans (faba beans, 64.88%; beans, 64.84%) yielded greater RS-III than maize (58.44%). The retrogradation process increased the crystallinity structure of the RS samples compared to their respective NS. Typical legume C pattern (faba bean and beans) and cereal A pattern (maize) of samples changed to an irregular polymorphic morphology type B + V, caused by retrogradation, and increasing RS content. As consequence, the digestibility of the retrograded samples was significantly reduced (approximately 50%) and increasing the amount of slow digestible starch fraction (SDS).

Chemical fertilizer reduction with organic fertilizer effectively improve soil fertility and microbial community from newly cultivated land in the Loess Plateau of China

Improving the soil quality of cultivated land generated by the Gully Land Consolidation Project could promote sustainable economic and ecological development in the hilly gully area of the Loess Plateau, China. A pot experiment with maize crop was conducted to assess the effects of different organic amendments and chemical fertilizer reduction on soil fertility and the microbial community in newly cultivated land, of which the amount of chemical fertilizer applied was half of the local conventional maize field (90 kg ha−1 of CO(NH2)2, 45 kg ha−1 of P2O5, and 60 kg ha−1 of K2O). The experiment involved six treatments: bare soil (CK), only maize (M), maize + chemical fertilizer (MF), maize + chemical fertilizer + organic fertilizer (MFO), maize + chemical fertilizer + biochar (MFB), and maize + chemical fertilizer + polyacrylamide (MFP). The results are as follows: (1) compared with the MF treatment, the MFO treatment exhibited the best effect on improving soil physicochemical properties, such as electrical conductivity (EC), soil organic carbon (SOC), nitrate nitrogen (NO3−-N), total nitrogen (TN), available phosphorus (AP) and available potassium (AK), followed by MFB and MFP. (2) The MFO treatment significantly (P < 0.05) improved the Species richness and Shannon indices of the bacteria, but its effects on fungal diversity index are not significant. (3) The MFO treatment increased the relative abundance of Betaproteobacteria, Alphaproteobacteria, Gammaproteobacteria and Gemmatimonadetes and decreased the relative abundance of Sordariomycetes and Agaricomycetes, and it also increased the functional abundance of Amino acid metabolism, Membrane transport, Xenobiotics biodegradation and metabolism, Undefined Saprotrophs and Arbuscular Mycorrhizal Fungi. (4) The TN and EC were the main driving factors of bacterial community structural variation, while TN and NO3−-N were the main factors for variation of fungal community structure. (5) The fresh weight and dry weight of maize increased significantly (P < 0.05) under all amendment treatments, among which the MFO treatment had the greatest effect. In conclusion, organic fertilizer application is the most effective measure for rapidly improving soil fertility and microbial community structure. Our findings have valuable implications for agricultural land productivity, food security and long-term sustainability of the environment.

Ovipositional responses of Spodoptera frugiperda on host plants provide a basis for using Bt-transgenic maize as trap crop in China

Spodoptera frugiperda, the pest fall armyworm (FAW), is widespread in more than 100 countries. To date, planting insect-resistant transgenic crops is one of the main control methods in its native countries. In this study we evaluated Bt-transgenic maize (Bt maize) and non-transgenic (conventional) maize and six other host plants in greenhouse pot experiments and field trials for oviposition preference by the Chinese populations of FAW. In laboratory trials, female moths preferred to oviposit on maize with no significant preference between conventional and Bt maize. However, after conventional and transgenic maize were exposed to FAW larvae and damaged, oviposition was significantly higher on transgenic maize than on the conventional one. Field trials showed that for plants less damaged at an early stage (seedling stage), oviposition of FAW on transgenic and conventional maize was significantly higher than that on wheat, sorghum, foxtail millet, peanut and soybean while showing no significant difference between transgenic or conventional maize. FAW adults mainly laid eggs on Bt maize, while the larval density and leaf damage rating or percentage of damaged plants were significantly lower than on conventional maize. Larval density and its damage on conventional maize were significantly higher than that on Bt maize and the other five hosts. Thus, maize is a highly preferred and suitable host for S. frugiperda feeding and ovipositing, and Bt maize can be used as trap crop to protect other crops.