Open-pollinated varieties

Reduction in maize grain losses could be enhanced through identification of existing resistant genotypes and pyramiding the resistance into elite materials. This study was carried out in two trials of 100 commercial hybrids and open pollinated varieties (OPVs), and 75 landraces to identify resistant genotypes and mechanisms of resistance to Chilo partellus maize stem borers. The trials were laid out in α-lattice designs, each replicated three times during the 2010/11 and 2012 rainy seasons. Each plant was artificially infested with five C. partellus neonates three weeks after planting. Data collected included leaf toughness, stem hardness, trichome density, stem sugar content, leaf damage, number of stem borer exit holes, tunnel length and grain yield. Data were analyzed using PROC GLM of SAS 2007 package and means separated using Fishers protected least significant difference test (LSD) at (P < 0.05). Canonical discriminant analysis was performed to discriminate the mechanisms evaluated. The most resistant genotypes were CIMMYT experimental resistant hybrid checks followed by landraces and the OPVs. Top 10 resistant commercial hybrids and OPVs were PH1, PH4, DHO1, DH04, DK8031, KDVI, KDV2, PH3253, ECA-Strigoff-VL and EEQPM-8-EA, while H629, H6212, KH 600-15A, H6213 and H6210 were the most resistant commercial hybrids. Canonical discriminant analysis identified percentage stem sugar content and trichome density as the most important resistance mechanisms for discriminating the genotypes. The resistant landraces and OPVs could be utilized in breeding for maize stem borer resistance, while the resistant commercial hybrids and OPVs could be recommended for production in the relevant ecologies in Kenya to curb maize stem borer related yield losses.

Commercial onion breeders limit their selection criteria by focusing almost exclusively on conventional farming. This raises the demand for certain well known varieties, but lowers the general diversity available on the mainstream market. A way to maintain biodiversity is to preserve old open-pollinated varieties. Through their distinct aroma and flavor, these plants are again drawing the interest of farmers and consumers alike, making them a viable alternative to commercial varieties. To assess yield and quality aspects of West-European open-pollinated onions, we have evaluated nine varieties and compared them against two of their commercial, well-established counterparts. The study included onion production on the field in South-West Germany, evaluation of the quality and flavor parameters, as well as a trained sensory taste panel. Results showed high diversity in yield and chemical properties of the studied onion varieties, where two varieties in particular, stood out significantly. Compared to the control, the variety “Birnförmige” performed best and demonstrated high concentrations of fructan and pyruvic acid, both known to have curative and medicinal properties. On the other end of the spectrum, the variety “Jaune des Cévennes” demonstrated low dry matter content, low concentration of enzymatically-produced pyruvic acid and a high bolting percentage. The study also confirmed the link between individual quality components in onion bulbs, including the significantly negative correlation between minerals (such as calcium and magnesium) and fructan.

Biofortified open pollinated maize varieties (OPV) could be used to address the problem of micronutrient deficiencies in developing countries. This study aimed at investigating the effects of matur...

Field experiments were conducted for 2years to examine the response of stigma in two different pollination systems, viz., CMS line (MJA5) and open-pollinated variety (Pusa Bold) of Indian mustard (Brassica juncea), to varying weather conditions created by different sowing dates. The CMS line MJA5 (female) with its male line in 8:2 (A:R) row ratio, and Pusa Bold in an isolated field were sown on 21st of October, 30th of October, and 18th of November in 2 consecutive years in North Indian condition. Temporal differences in sowing provided differed weather conditions during flowering, which resulted in variations in the duration to attain the peak flowering stage. Stigma was receptive for longer duration (8days from the day of anthesis) in CMS line which needs an external pollen source for fertilization to happen, whereas it was only 4days in open-pollinated variety, assessed in terms of siliqua set and number of seeds/siliqua. Substantial effect of sowing date on stigma receptivity was observed; it was longer in plants sown during October in comparison to those of November in both years. The energy requirement parameters, viz., growing degree days and photo-thermal unit, confirmed that plants sown later failed to accumulate sufficient energy for satisfactory phenological growth and for good seed development.

We assessed the impact of environmental conditions and agronomic traits on maize grain quality parameters. The study was conducted using genotypes with distinct genetic constitutions developed specifically for late sowing in semi-arid environments. We evaluated the agronomic, physical, and chemical characteristics of eight maize open-pollinated varieties, six inbred lines, and three commercial hybrids. The yield of the open-pollinated varieties showed a positive correlation with protein content (r = 0.33), while it exhibited a negative correlation with the carbohydrate percentage (r = -0.36 and -0.42) in conjunction with the inbred lines. The flotation index of the hybrids was influenced primarily by the environmental effect (50.15%), whereas in the inbred lines it was nearly evenly divided between the genotype effect (45.51%) and the environmental effect (43.15%). In the open-pollinated varieties, the genotype effect accounted for 35.09% and the environmental effect for 42.35%. The characteristics of plant structure were associated with grain quality attributes relevant for milling, including hardness and test weight. Inbred lines exhibited significant genotype contributions to grain hardness, protein, and carbohydrate content, distinguishing them from the other two germplasm types. These associations are crucial for specific genotypes and for advancing research and development of cultivars for the food industry.

In the dry savannas of West and Central Africa, where low soil fertility, unpredictable rainfall, weed competition and recurrent drought are major constraints to maize production, the development of tropical maize genotypes with high and stable yields under drought and low-nitrogen condition is very important since access to these improved genotypes may be the only affordable alternative to many small scale farmers. Field trials were conducted in 2002 and 2003 at Ikenne southwestern Nigeria to investigate the effect of weed pressures and drought stress on 2 maize (Zea mays L.) hybrids (9134-14, 9803-9) and 2 open-pollinated varieties (STREVIWD, IYFDCO1). Irrigation was withdrawn 4 weeks after planting (about four weeks to mid-flowering) in the drought stress while the adjacent watered treatment had irrigation throughout the growing period. The weed pressures were the completely weeded plots (hand weeding every week) and weedy plots (weeded once, 2 weeks after planting). The experiment was a split plot in a randomized complete block design with four replicates. Drought stress reduced the stover weight and grain yield of the maize cultivars by 6% and 34% respectively. Weed-free plots had maize with higher agronomic traits than unweeded treatments. Hybrid 9803-9 was more susceptible to drought and weed stress as indicated in the stover weight and grain yield. STREVIWD an open-pollinated variety (OPV) and Hybrid 9134-14 had superior performances in terms of grain yield and shorter anthesis silking interval. Soil moisture content was higher in the unweeded plots while the uptake of moisture was highest in drought susceptible hybrid 9803-9. Irrespective of the genotypes, maize (hybrid and OPV) was more tolerant to drought in a weed-free environment than in unweeded conditions. There existed a negative but significant correlation between weed biomass and chlorophyll content (−0.29, P < 0.01), grain yield (−0.45, P < 0.05), ear plant−1 (−0.27, P < 0.05) and kernel-number (−0.366 P < 0.01).

During the past 70 years, professionally trained plant breeders in the United States made dramatic genetic improvements in corn (Zea mays L.). This is compared with no gains realized on a national basis from the 1860s to the 1930s when most of the corn breeding was done by farmers. The reason for this difference in results is largely attributable to adoption of some basic scientific principles by the professional breeders. This lesson is located in the Library of Crop Technology (http://croptechnology.unl.edu) and is the first in a series of lessons designed to explain these principles. This lesson is written at an introductory level targeting those people without any prior training in genetics, breeding, or related sciences. After completing this lesson, a person should be able to do the following: Describe the basic anatomy and reproductive biology of a corn plant. Name the two races of corn that are the parents of the Corn Belt Dent race. Define what is meant by open‐pollinated variety (OPV) and name several historically important open‐pollinated varieties (OPVs). Discuss two reasons why grain productivity did not increase in the United States from 1870 to 1930. Define inbreeding and the consequences of inbreeding in corn. Describe how to develop an inbred and a single‐cross hybrid of corn. Name three reasons for the remarkable gains made in corn performance from 1930 to the present. A bank of quiz questions focused on these points is a part of this lesson.

The variability of seed storage-proteins of 21 pearl millet genotypes were analyzed by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). Electrophorogram for 21 Pearl millet genotypes (seven hybrids, six female parent, five male parent and three Open Pollinated Variety(OPV)) were scored and Jaccard‘s similarity index (JSI) was calculated. Genetic diversity of Pearl millet genotypes was evaluated by constructing the dendrogram with Unweighted Pair Group Method Arithmetic Average (UPGMA) algorithm using NTSYSPC version 2.01 software. Six mobility bands that were polymorphic (Rm=0.33, 0.39, 0.43, 0.51, 0.69 and 0.75) were used for genotyping. Though it proved an efficient method to distinguish a few genotypes (H 90/4-5, H77/833-2, G 73-107, H 77/29-2, ICMA 95222A, HHB 146, MS 843A and ICMA 89111A) based on banding pattern. Intensity of bands were also some extant helped to differentiate genotypes especially Band with Rm value of 0.43 was light for H 77/29-2, band with Rm value of 0.51 was very light for G73-107 and band with Rm value of 0.75 was medium intensity for H 90/4-5. It is concluded that seed storage protein profiles could be useful markers in the studies of genetic diversity and classification of Pearl millet genotypes.

Maize production and productivity in western and southwestern parts of Ethiopia is affected by, the potential outbreaks of major diseases such as ear rot caused by Fusarium spp., dominantly Fusarium and Gibberella ear rots. Hence, maize genotypes including (commercial hybrids, open pollinated varieties (OPVs) and elite pre commercial hybrids) collected from Ethiopia were evaluated at Bako, Jimma and Hawassa Agricultural Research Centers in 2021 and 2022 cropping seasons to assess their resistance to Gibberella ear rot (GER) and Fusarium ear rot (FER). Local isolates of F. verticillioides and F. meridionale were used and the genotypes were inoculated by introducing conidial suspensions into the silk channels of the primary ears. Twenty (20) maize genotypes were used in this study arranged in split-plot design in all the environments. Maize genotypes were randomly assigned to main plots units and fungal species to subplot units. Result showed that maize genotypes exhibited resistant (R), moderately resistant (MR), moderately susceptible (MS) and susceptible (S) reactions to the inoculation. The percentage of resistant maize genotypes ranged from 25 to 45% for GER and 15 to 25%for FER across different environments. The genotypes BH661, BHQP548, CML 395/CML 202//CML 536-#, Damot (P3506W), DK 777, and Gibe3 exhibited lesser disease severity (R or MR) in most of the environments than did the susceptible genotypes (CML 395/CML202//P3812W(F2)-24–2-2–1-1–1-B-#, BH660, and BHQPY545) across all environments. Only one hybrid (BH660) showed high susceptibility to F. verticillioides, and another (BHQPY545) displayed high susceptibility to F. meridionale at Hawassa and Jimma. From the present study, it can be concluded that, the majority of maize cultivars displayed susceptibility to ear rot caused by at least one of these Fusarium spp. in most environments. Additionally, FER severity was significantly (P < 0.001) and positively (r = 0.45) associated with GER severity, suggesting that both pathogens share the same mechanisms of disease resistance. Moreover, agronomic traits such as kernel texture (r = 0.401, 0.261), ear aspect (r = 0.024, 0.310), husk cover (r = 0.147, 0.268), date of anthesis (r = 0.149, 0.09), and date of silking (r = 0.153, 0.09) were positively and significantly (p < 0.001) associated with GER and FER severity, respectively. While ear height was significantly (p < 0.001) and negatively (r = -0.164, -0.158) associated with GER and FER severity, respectively. Thus, selecting for resistance to one fungal species would likely result in indirect selection for resistance to the other fungal species. Therefore, it is suggested that, the usage of these maize genotypes in traditional breeding programs might face challenges due to undesirable gene linkages. Hence, further research on molecular markers may be necessary to overcome these obstacles and fully leverage the potential of these genotypes in breeding programs in the country.

&lt;p&gt;Previous, research focused mainly on the effects of conservation agriculture (CA) and conventional practices (CP) on crop yield mostly. A study was conducted at five sites in Zimbabwe from 2012 to 2014 to investigate effects of CA and CP practices on emergence, chlorophyll content, early vigour and grain yield of different maize varieties using 12 hybrids and 4 open pollinated varieties (OPVs). The experiment was laid as a 4 × 4 alpha lattice design with three replications. Emergence was higher under CA (75%) at University of Zimbabwe (UZ) in 2012/13 and Domboshawa Training Centre (DTC) (67%) compared to CP (71% and 39% respectively). Lower early plant vigour was observed under CA compared to CP at most sites. CA had lower leaf chlorophyll content during the early crop growth stages compared to CP. However, at some instances, CA had higher leaf chlorophyll content (45 units) than CP (35 units) at 78 days after sowing in Zimuto 2012/13. For maize yield, CA outperformed CP on a sandy loamy soil (3050 kg ha&lt;sup&gt;-1&lt;/sup&gt; vs 2656 kg ha&lt;sup&gt;-1&lt;/sup&gt;) and clay soil (4937 kg ha&lt;sup&gt;-1&lt;/sup&gt; vs 4274 kg ha&lt;sup&gt;-1&lt;/sup&gt;). However, on a sandy soil, CP outperformed CA (1764 vs 1313 kg ha&lt;sup&gt;-1&lt;/sup&gt;). Our results suggest that tillage effects on early maize plant vigor, leaf chlorophyll content and the final yield can be site and season specific. Furthermore, a delay of nutrient release for plant uptake under CA systems was found and potentially implies investigations of new fertilization strategies for such cropping systems.&lt;/p&gt;

Five International Institute of Tropical Agriculture (IITA) drought tolerant and open pollinated varieties (OPVs) (lines) and four local varieties with various level of susceptibility to drought (testers) were used. These maize varieties were crossed using a line x tester mating design during the 2007 cropping season to determine the general combining ability (GCA) and specific combining ability (SCA); also the level of heterosis was investigated. Parental lines and hybrids were evaluated in Biu in 2008 and 2009 cropping seasons. Results from the analysis of variance and combining ability shows that there was high and significant level (P&lt; 0.05) of genetic variability among the parental lines used and their hybrids in days to tasseling, days to silking, anthesis silking interval (ASI), plant height, ear height, weight of cobs, dehusked cobs and grain yield, thus suggesting the possibility for genetic improvement. The study established that, there were significant (P&lt;0.05) differences of GCA effects of parents and that of SCA effects of hybrids. Estimates of GCA were consistently lower than SCA effects in almost all the traits evaluated. This suggests that high performing hybrids such as EVDT-99WSTRQPMC0 x EX-DAMBOA WHITE, EVDT-99WSTRC0 x EX-DAMBOA YELLOW andTZE-COMP3DTC1 x EX-DAMBOA WHITE may be used to develop potential varieties. The parents: EVDT-99WSTRC0, EVDT-99WSTRQPMC0, TZE-COMP3DTC1 and EX-BIU WHITE were identified as the best general combiners in terms of GCA for days to tasseling, days to silking, ASI, plant height, ear height, dehusked cobs and grain yield. &nbsp; Key words: Maize, combining ability, additive, non-additive genetic effects, drought tolerance.

IntroductionFertilizer use in sub-Saharan Africa (SSA) is the lowest in theworld and has stagnated. Consequently low nitrogen (N) stress is one of the principal constraints to maize yields in this region. Therefore improving nitrogen use efficiency of maize varieties will result in higher nitrogen recovery rates, leading to less leaching of nitrogen as well as loss through nitrification and ammonification. This study aimed to: 1) Investigate the relationship between grain yield under low N and optimal conditions; and 2) Establish the level of variability in low N tolerance among elite Eastern and Southern African (ESA) maize varieties. MethodsFifty-eight paired trials, each consisting of 40 to 65 maize hybrids, were conducted under low N and optimal (i.e.,high N) conditions in five countries, in Eastern and Southern Africa during 2013-2015.Results and discussionThe level of yield reduction as a result of low N stress ranged from 8% to 91% across the 58 paired trails. Grain yield of hybrids ranged from1.69Mg ha-1 to 3.44 Mg ha-1 in the early maturity group and 1.71 Mg ha-1 to 3.35 Mg ha-1 in the intermediate to late maturity group, with heritability ranging from 0.25 to 0.53 and 0.29 to 0.76, in the respective two maturity groups. Under the low N stress. Pre-commercial hybrids that were bred for low N tolerance performed better than the old commercial hybrids and open pollinated varieties (OPVs). These results suggest that if more effort is devoted to selecting maize under low N conditions, significant yield gains can be realized with profound impact on maize productivity in SSA.

The maize database, first of its kind in India, is a central repository for cultivars i.e. hybrids and open pollinated varieties (OPVs) notified for cultivation in India since the inception of All India Coordinated Maize Improvement Project (AICMIP) in 1957. The database includes the information on cultivars developed from public as well as private breeding programmes. Besides, information on registered germplasm is also given. The database carries image gallery showcasing photographs of cobs/standing crop of the public-bred cultivars released after 1993.The database also presents information about adaptability of cultivars, average yield and disease, and insect-pest resistance along with the parental materials used in breeding programmes. Information on 31 descriptors as per Distinctivity, Uniformity and Stability (DUS) tests in respect of parental lines and their hybrids that were filed for protection under “Protection of Plant Varieties and Farmers Rights Act, 2001” (PPVFRAct, 2001) has been supplemented. In addition, the database provides contact information on developers of the notified cultivars thereby facilitating interactions among the members of maize community. The information contained within maize database can be accessed at on-line expert system called maize AGRIdaksh (www.iimr.res.in/maizeexpertsystem/www.agridaksh.iasri.res.in/maize). Information on notified cultivars (1961-2010) parental lines and cultivars (1993-2012) filed under PPVFRAct, 2001 can also be accessed at www.iimr.res.in/maizeexpertsystem/maize hybrids and composite varieties released in India. Whereas, information about registered germplasm (2003-2012) can be accessed at www.iimr.res.in/publications.

The effects of packaging materials [Corrugated fibre boxes (CFB), non-perforated polypropylene pouches (NPPP), perforated polypropylene pouches (PPP), plastic crates (PC), jute bags (JB)] were assessed on quality attributes in open pollinated (OP) and hybrid tomato (Solanum lycopersicum L.) cultivars during ambient storage (24-32oC and 70- 85% RH). Tomato OP variety, Kashi Hemant had shown maximum PLW (65.2%) in PC while coded IIVR hybrid 1 exhibited minimum PLW (1.3%) in NPPP after 20 days of storage at ambient storage temperature. The maximum increase in ‘a’ value was also obtained in PC followed by JB, CFB, PPP and NPPP. Maximum (14.7-25.0 mg/100g) increase in ascorbic acid was obtained in hybrid Kashi Abhiman during 25 days of storage in NPPP whereas, OP variety Kashi Amrit had shown minimum increase (10-18.5 mg/100g) in ascorbic acid in PC after 15 days of storage.

Use of small doses of imazapyr and pyrithiobac for seed coatings of imazapyr-resistant maize hybrids (IR-Maize) offers an effective means to control Striga hermonthica. Field trials were conducted in Bauchi and Kano States of Nigeria in 2014 and 2015 under heavy Striga infestation to evaluate the potential effectiveness of herbicide coated hybrids maize on Striga control in farmers’ field. Results showed that herbicide coated seeds reduced number of emerged Striga per m2 and Striga damage symptoms in farmers’ fields in all the locations. In Kano the number of emerged Striga was 4.9 to 7.9 times less in herbicide treated hybrids in comparison with those of the same hybrids planted without herbicide treatment. The Striga-resistant open pollinated variety (OPV) (TZL COMP1 SYN) had 6.7 to 8.0 times more Striga than the treated hybrids. In Bauchi, the number of emerged Striga on the untreated IR-maize hybrids were over four-times higher on the treated IR-maize hybrids than on the untreated hybrids. The Striga-resistant OPV check had four-times more Striga than the treated IR-maize hybrids and twice more than the untreated IR-maize hybrids across the two years. However, the effects of herbicide seed coating on grain yields were not consistent because of strong seasonal effects. The result revealed that coating of imazapyr-resistant hybrid maize seeds with imazapyr was effective in reducing Striga infestation in farmers’ fields. Although herbicide seed coating did not give consistent yield advantages of the hybrids over the untreated checks, a combination of herbicide seed treatment and genetic resistance to Striga would serve as an effective integrated approach that could significantly reduce the parasite seed bank from the soil and prevent production of new seeds. The IR-hybrids and the OPV checks contained Striga resistance/tolerant genes that protected them against drastic yield loss in the Striga infested fields in both Bauchi and Kano.