Diallel analysis of grain filling rate and grain filling period in tropical maize (<Emphasis Type="Italic">Zea mays</Emphasis> L.)

Grain yields of maize in the lowland tropics are generally limited by short days and high temperatures that minimize durations of incident light. Little has been published on the effects of this limiting environment on the genetics of grain filling rate (GFR), and grain filling period (GFP) in tropical maize germplasm. This study sought to address these limitations. A set of 8 elite maize inbreds of tropical origin and their 28 diallel hybrids were grown in three seasons at Waimanalo, Hawaii, USA. Seasonal differences included > 100% differences in values of photosynthetic active radiation (PAR) during grain formation. Information was sought on the performance variations and the genotype by season interactions for GFR, GFP, days to mid-silk (DTS), kernel weight, with estimates of general (GCA) and specific combining ability (SCA) and their interactions with seasons. Significant differences occurred for inbreds, hybrids, and genotype by season interactions, GCA and SCA effects and their interactions with seasons, which could be attributed primarily to the differences in PAR values among seasons in Hawaii during grain filling. Additive genetic effects predominated for GFR and GFP. Breeding approaches that take advantage of additive gene effects including hybrid breeding with evaluations in multiple Hawaii seasons may be used to alter GFR and GFP.     

Development of in vivo haploid inducers for tropical maize breeding programs

Lack of adapted haploid inducers currently impedes adoption of the doubled haploid technology in tropical maize breeding programs. Our objective was to generate inducers with improved adaptation to tropical conditions. We developed segregating generations from crosses between temperate inducers having haploid induction rates (HIR) of 8–10 % and tropical CIMMYT maize lines (CML; HIR = 0 %) and evaluated these for HIR and agronomic performance under tropical lowland field conditions. The applied pedigree breeding scheme comprising mass selection on individual F₂ plants for highly heritable and visually scorable traits, followed by family-based selection for HIR and other agronomic characteristics in advanced selfing and backcross (BC) generations seems highly suitable for breeding improved haploid inducers with adaptation to different agroecologies. The most advanced tropical inducer candidates (TIC) combine HIR of up to 10 % with improved pollen production, disease resistance, and plant vigor compared to temperate inducers under tropical conditions. Agronomic characteristics were significantly improved in the BC to CML compared to BC to inducers, while mean HIR of both populations were similar, indicating that backcrossing to the adapted parent was suitable to improve adaptation of new inducers without sacrificing high HIR. When screening random open-pollinated maize accessions, HIR of up to 3 % were observed, suggesting that novel genetic variation may be present in maize accessions that could be exploited to improve HIR in maize. In conclusion, tropical inducer development proceeds well, but evaluation of TIC in multi-environment trials needs to be completed before large-scale dissemination can commence.     

Gene action and reciprocal effects for ear rot resistance in crosses derived from five tropical maize populations

Devastating maize grain yield and quality losses are caused by Aspergillus flavus, Fusarium verticillioides and Stenocarpella maydis ear rots especially in tropical countries. Therefore, combining ability of tropical maize populations for ear rot severity and ear rot-related traits was investigated. Ten full-sib progenies, comprising one resistant and one susceptible from each of the five populations, were selected for mating in a 10 × 10 full diallel. The full-sib progeny crosses were evaluated across two environments with two replications in Zambia. To determine resistance across three ear rots that occur together in Zambia, the crosses were artificially inoculated with a mixture of Aspergillus flavus, Fusarium verticillioides and Stenocarpella maydis isolates. There were marked differences between environment main effects and their interaction with GCA and SCA effects were highly significant, suggesting observation of genotype × environment interaction effects. Both additive and non-additive gene effects were significant for ear rot severity. Highly significant reciprocal differences were also revealed, suggesting that cytoplasmic gene effects and their interaction with nuclear genes were responsible in modifying resistance across the three ear rot diseases in the full-sib progenies that were derived from the five tropical maize populations.     

Combining ability of low phytic acid (<Emphasis Type="Italic">lpa1</Emphasis>-<Emphasis Type="Italic">1</Emphasis>) and quality protein maize (QPM) lines for seed germination and vigour under stress and non-stress conditions

Grain yield is more likely to be compromised by poor seed germination and vigour in low phytic acid (LPA) and quality protein maize (QPM) than normal maize (Nm), especially when grown under stressful tropical environmental conditions. The objectives of this study were to determine the effect of stress conditions on seed germination and vigour traits (percentage germination, seedling dry weight, average root and shoot length and vigour index) and to determine the GCA effects of the parental lines and SCA effects of the crosses. A ten parent half diallel (LPA, Nm, QPM lines) was subjected to the standard germination (non-stress) and accelerated aging (AA) (stress) tests. All seed lots were at the same physiological age and produced under the same season and conditions. Genotypic and group differences were investigated. General combining ability (GCA) and specific combining ability (SCA) effects were significant (P ≤ 0.001) for all traits under both stress and non-stress conditions indicating that both additive and non-additive gene effects were significant. Generally SCA effects were superior for all traits. The LPA lines displayed 61 % reduction in germination and 23–52 % reduction in vigour under stress conditions thereby underscoring challenges that are expected in deploying LPA maize in stress conditions. However, LPA line CM 31 exhibited large positive and mostly significant GCA effects, while two LPA × LPA crosses showed significant positive SCA effects. Results indicate breeding is required to improve both germination and vigour of the LPA lines to adapt them to tropical conditions that are generally stress-prone.     

Combining ability and testcross performance of drought‐tolerant maize inbred lines under stress and non‐stress environments in Kenya

Drought and poor soil fertility are among the major abiotic stresses affecting maize productivity in sub‐Saharan Africa. Maize breeding efforts at the International Maize and Wheat Improvement Center (CIMMYT) have focused on incorporating drought stress tolerance and nitrogen‐use efficiency (NUE) into tropical maize germplasm. The objectives of this study were to estimate the general combining ability (GCA) and specific combining ability (SCA) of selected maize inbred lines under drought stress (DS), low‐nitrogen (LN) and optimum moisture and nitrogen (optimum) conditions, and to assess the yield potential and stability of experimental hybrids under these management conditions. Forty‐nine experimental three‐way cross hybrids, generated from a 7 × 7 line by tester crosses, and six commercial checks were evaluated across 11 optimum, DS and LN sites in Kenya in 2014 using an alpha lattice design with two replicates per entry at each site. DS reduced both grain yield (GY) and plant height (PH), while anthesis–silking interval (ASI) increased under both DS and LN. Hybrids ‘L4/T2’ and ‘L4/T1’ were found to be superior and stable, while inbreds ‘L4’ and ‘L6’ were good combiners for GY and other secondary traits across sites. Additive variance played a greater role for most traits under the three management conditions, suggesting that further progress in the improvement of these traits should be possible. GY under optimum conditions was positively correlated with GY under both DS and LN conditions, but GY under DS and LN was not correlated. Our results suggest the feasibility for simultaneous improvement in grain yield performance of genotypes under optimum, DS and LN conditions.     

Assessing the suitability of stress tolerant early-maturing maize (Zea mays) inbred lines for hybrid development using combining ability effects and DArTseq markers

Identification of hybrids for commercialization is crucial for sustainable maize production in sub-Saharan Africa (SSA). One hundred and ninety test crosses, 10 tester × tester crosses + 10 hybrid checks were evaluated across 11 environments, 2017 to 2019. Inheritance of grain yield under Striga infestation, optimal and across environments was influenced by additive genetic action, but there was greater influence of nonadditive gene action under drought stress conditions. Nine, seven and two inbreds had significant and positive general combining ability (GCA) effects for grain yield under Striga-infested, optimal and drought stress environments, respectively, and would contribute high grain yield to their progenies. Heterotic grouping methods based on specific and GCA, GCA effects of multiple traits and DArTseq markers classified the inbreds into five, three and two heterotic groups, respectively, across research conditions. The DArTseq markers method that classified the inbred lines into two major heterotic groups and was one of the most efficient methods should be adopted for practical purposes in maize breeding programmes in SSA. Hybrids TZEI 7 × TZdEI 352, TZEI 1238 × TZEI 7 and TZEI 1252 × TZEI 7 had outstanding grain yield under contrasting environments and should be tested on-farm for commercialization in SSA.     

导入热带种质的温带玉米自交系的利用潜力

用5个热带及亚热带玉米自交系和5个导入热带种质并经连续回交改良的温带玉米自交系, 采用Griffing双列杂交方法III杂交, 共配制90个杂交组合。2008年、2009年以大面积推广杂交种云瑞6号为对照, 对供试自交系进行配合力、杂种优势及利用潜力研究。结果表明, 导入热带种质并经连续回交改良的温带玉米自交系YML598、YML58的多数性状一般配合力效应为极显著正值, 在杂交育种中具有较大的利用潜力;单株产量配合力效应值与诸多产量影响因素的配合力效应值密切相关, 雌雄间隔期、秃尖与单株产量呈负相关, 而其他性状与单株产量呈正相关;产量对照优势H≥10%的组合大多为热带、亚热带种质×改良温带种质, 单株产量特殊配合力效应为极显著正值的组合均为热带、亚热带种质×改良温带种质, 说明热带、亚热带玉米种质与经热带种质改良后的温带玉米种质之间仍具有较强的杂种优势, 且导入热带种质的温带系与热带、亚热带供体系的杂种优势仍然存在, 其所属的杂种优势群并未改变。以热带、亚热带玉米种质为供体, 采用连续回交的方法改良温带玉米自交系是利用热带、亚热带玉米种质的有效方法。     

Genetic analysis of drought-adaptive traits at seedling stage in early-maturing maize inbred lines and field performance under stress conditions

Maize hybrids that are tolerant to drought at the seedling stage are needed to boost productivity in the rainforest agro-ecology of West Africa. Genetics of tolerance of maize seedling to drought stress is not well understood and is poorly documented. The objectives of this study were to screen early-maturing maize lines for seedling drought tolerance, determine the inheritance and the combining ability of selected inbred lines, and evaluate the performance of seedling drought-tolerant hybrids under field conditions. Forty-nine early maize lines were screened for drought tolerance at the seedling stage. Ten drought-tolerant and two susceptible inbred lines were selected and used in diallel crosses to generate 66 hybrids. The twelve inbred lines and their hybrids were evaluated under induced drought at seedling stage in the screen house and under marginal growing conditions on the field for two seasons. Data collected were subjected to analysis of variance using the DIALLEL-SAS program. Mean squares for both GCA and SCA were significant for most traits in all research environments, indicating that additive and non-additive gene actions are controlling seedling traits under stress conditions. However, for most traits, SCA was preponderant over GCA in all environments, indicating overdominating effect of non-additive gene action. Which in turn implied that the best improvement method for the traits is hybridization. Inbred TZEI 7 had the best GCA effect for seedling traits under screenhouse conditions and for grain yield and other agronomic traits under drought conditions in the field. Hybrids TZEI 357?×?TZEI 411 and TZEI 380?×?TZEI 410 showed superior SCA effects under screen house conditions. In conclusion, the study established wide genetic variability for drought tolerance at seedling stage among tropical early-maturing maize germplasm however, the non-additive gene action was more important for most seedling traits.     

Relative efficiency of maize and Imperata cylindrica for haploid induction in Triticum durum following chromosome elimination‐mediated approach of doubled haploid breeding

Intergeneric hybridization in seven diverse durum wheat genotypes was carried out using two composite varieties of Himalayan maize, viz., Bajaura Makka and Early Composite, and a wild grass, Imperata cylindrica, as pollen sources. Observations related to various haploid induction parameters put forth I. cylindrica as significantly better pollen source for haploid induction in durum wheat over maize in terms of pseudoseed formation (46.93%), embryo formation (38.06%), haploid regeneration (40.42%) and haploid formation efficiency (7.44%). The line x tester analysis revealed that both male and female genotypes had significant effects on all haploid induction parameters except haploid formation frequency in later. Among the pollen sources, I. cylindrica emerged as best combiner based on GCA values when compared with the two Himalayan maize composites. Durum wheat genotype, A‐9‐30‐1 was recognized as the best general combiner followed by PDW 314. The present investigation proposed durum wheat × I. cylindrica as a superior technique over maize‐mediated system, and its large‐scale use can open a new horizon in the sphere of durum wheat doubled haploidy breeding programme.     

Genetic analysis of resistance to nematodes in inbred maize (<Emphasis Type="Italic">Zea mays</Emphasis> L.) and maize hybrids

Nematodes cause substantial grain yield loss in susceptible maize (Zea mays L.) cultivars. This study was conducted to estimate general combining ability (GCA), specific combining ability (SCA) and genetic effects associated with nematode resistance in maize. The 30 F ₁ hybrids generated from a 6 × 6 diallel and two local checks were evaluated in 2009 at three sites in Uganda. A split plot design was used with nematode treatments serving as whole plots and the hybrids as subplots but arranged in an 8 × 4 spatially adjusted alpha-lattice design. The experiment was replicated three times. Results showed GCA to be important for the reduction of P. zeae and Meloidogyne spp. densities and increase of root mass, with a contribution of 72 to 93% of the phenotypic variance. Inbreds MP709 and CML206 had the highest GCA for Pratylenchus zeae resistance, whereas for grain yield, it was CML444, CML312 and CML395 that were outstanding. The SCA influenced plant height and grain yield under nematode infestation, contributing 43 and 58% of the phenotypic variance, respectively. Observed reciprocal differences due to maternal effects also played a role in influencing the grain yield under nematode infestation. Overdominance genetic effects explained the non-additive variance recorded for the plant height, grain yield, number of root lesions, and P. zeae and Meloidogyne spp. densities under nematode infestation. The parents MP709, CML206, 5057, and CML444 contributed most of the dominant genes for the P. zeae resistance in all their crosses. The parent CML444 contributed most of the dominant genes for improved grain yield in all of its crosses. The high GCA effects among some parents support their utility in breeding of widely adapted nematode-resistant cultivars. The dominant genes and SCA effects would favour pedigree and various sib tests to improve grain yield under nematode pressure.     

Combining ability and heterotic patterns of extra-early maturing white maize inbreds with genes from <Emphasis Type="Italic">Zea diploperennis</Emphasis> under multiple environments

Low soil nitrogen (Low N), Striga hermonthica and recurrent drought are major constraints to maize production and productivity in sub-Saharan Africa (SSA). Only a few extra-early maturing hybrids with combined tolerance to drought, Striga and low N have been commercialized in SSA. The objectives of the study were to determine the general combining ability (GCA) and specific combining ability (SCA) effects of grain yield and other traits, classify the inbreds into heterotic groups using the SCA effects of grain yield, and the heterotic group’s SCA and GCA of grain yield (HSGCA) methods, and examine the performance of hybrids under contrasting environments. Sixty-three extra-early white maize inbred lines containing genes from Zea diploperennis were crossed to four elite testers to obtain 252 single-cross hybrids and evaluated together with four checks at four locations for 2 years under drought, Striga-infested, low N and optimal environments in Nigeria. The GCA and SCA effects were significant (P ≤ 0.01) with preponderance of GCA over SCA effects for all measured traits indicating that additive genetic effects were predominant in the lines under all the contrasting environments. The HSGCA was more efficient than the SCA method in the classification of the inbreds into heterotic groups. The hybrids TZdEEI 74 × TZEEI 13 and TZdEEI 74 × TZEEI 29 were high yielding and most stable across research environments. These hybrids should be further evaluated in on-farm trials to confirm the consistency of performance for commercialization in SSA.     

Combining ability of maize inbred lines containing genes from Zea diploperennis for resistance to Striga hermonthica (Del.) Benth

Maize ( Zea mays ) is a staple food crop in sub-Saharan Africa, but its production is threatened by Striga hermonthica (Del.) Benth. Transfer of resistance genes from wild relatives may increase resistance to S. hermonthica in tropical maize. The objective of this study was to determine the combining ability of resistance to S. hermonthica among lines containing Zea diploperennis and tropical germplasm. Forty-five diallel crosses of 10 inbred lines were evaluated in an alpha-lattice design with and without artificial Striga infestation at two locations each in the Republic of Benin and Nigeria for 3 years. Results of analyses showed that only general combining ability (GCA) mean square was significant (P = 0.01) for number of emerged Striga plants (NESPP), while both GCA and specific combining ability (SCA) mean squares were significant for host damage score (HDS) and grain yield under Striga infestation. The ratio of GCA to SCA mean squares for the three traits varied from 3.5 to 57.5. Although GCA × environment interaction was significant for the three traits, two inbred lines containing Z. diploperennis (ZD 551) and tropical (TZL TC 87) germplasm had negative and significant GCA effects for NESPP and HDS and positive GCA effects for grain yield under Striga infestation in the two countries. Correlation between NESPP and HDS was strong and significant ( r  = 0.87, P = 0.01). Our results highlight the importance of harnessing useful genes from wild relatives to improve resistance to S. hermonthica in adapted maize germplasm.     

Inheritance of threshing percentage in pearl millet

Summary The threshing percentage (TH%) has been suggested as a selection criterion to identify the pearl millet (Pennisetum glaucum (L.) R.Br.) lines with improved ability to fill and set grains under water limiting conditions. In this study, eight genetically diverse pearl millet inbreds and their 28 crosses produced by half diallel crossing design were used to examine range in TH%, to evaluate general combining ability (GCA) of parents and specific combining ability (SCA) effects of crosses. The results showed significant variation among parental lines for TH%. The inbreds differed for their GCA effects and crosses for their SCA effects. Parents with high TH% and positive GCA effects were identified. The results of the study revealed that both additive and dominance components, with the preponderance of later, were important in the inheritance of TH%. Heritability in narrow sense was moderate (55%) indicating that selection for high TH% might be effective.     

Combining ability,heterosis and genetic diversity in tropical maize (<Emphasis Type="Italic">Zea mays</Emphasis> L.) under stress and non-stress conditions

Drought and low soil fertility are considered the most important abiotic stresses limiting maize production in sub-Saharan Africa. Knowledge of the combining ability and diversity of inbred lines with tolerance to the two stresses and for those used as testers would be beneficial in setting breeding strategies for stress and nonstress environments. We used 15 tropical maize inbred lines to (i) evaluate the combining ability for grain yield (GY), (ii) assess the genetic diversity of this set of inbred lines using RFLP, SSR, and AFLP markers, (iii) estimate heterosis and assess the relationship between F₁ hybrid performance, genetic diversity and heterosis, and (iv) assess genotype × environment interaction of inbred lines and their hybrids. The F₁ diallel hybrids and parental inbreds were evaluated under drought stress, low N stress, and well-watered conditions at six locations in three countries. General combining ability (GCA) effects were highly significant (P < 0.01) for GY across stresses and well-watered environments. Inbred lines CML258, CML339, CML341, and CML343 had the best GCA effects for GY across environments. Additive genetic effects were more important for GY under drought stress and well-watered conditions but not under low N stress, suggesting different gene action in control of GY. Clustering based on genetic distance (GD) calculated using combined marker data grouped lines according to pedigree. Positive correlation was found between midparent heterosis (MPH) and specific combining ability (SCA), GD and GY. Hybrid breeding program targeting stress environments would benefit from the accumulation of favorable alleles for drought tolerance in both parental lines.     

Molecular identification of Pm12-carrying introgression lines in wheat using genomic and EST-SSR markers

The traditional process of obtaining maize hybrids involves the generation of inbred lines through successive generations of selfing and subsequent testcrosses in order to identify the best combining ability by allelic complementation. A fast alternative to obtain inbred lines is to induce the formation of haploids followed by chromosome doubling. However, even with the aid of haploid-inducing genetic sources, this strategy has not been widely used in maize breeding programs, partly due to difficulties inherent to haploid generation and identification. In order to evaluate the possibility of using dihaploids to generate homozygous maize tropical lines, we used the androgenetic haploid inducer line W23 as a female parent in crosses with the tropical single-cross hybrid BRS1010. Within the progeny of these crosses, 462 seeds were phenotypically selected as putative haploids by the purple-colored endosperm and colorless embryo conditioned by the R1-nj gene. Among these, only four individuals were confirmed as being haploids using SSR markers, chromosome counting and flow cytometry, showing that the phenotypic marker was not efficient in detecting haploids in the tropical maize genotype used. All four haploids as well as some diploid plants presented reduced size, corroborating the difficulties for haploid identification by phenotypic evaluation. Genetic diversity analysis revealed by SSR markers divided the haploids in two groups represented by flint and dent maize inbred lines, which could be helpful in identifying complementary dihaploid lines. The present article demonstrates that a combination of haploid production and SSR fingerprinting is a feasible strategy for maize hybrid development in tropical germplasm.     

Diallel analysis of Fusarium head blight resistance in genetically diverse winter wheat germplasm

New sources of partial resistance to Fusarium head blight (FHB) in wheat have been identified over the past decade; however, little is known of their breeding value. A 20 parent partial diallel that included resistant genotypes from the U.S., Europe, China and South America was used to evaluate the potential of these sources of resistance as parents in wheat breeding programs. Eight plants replication⁻¹ of each of 190 crosses and 20 parents were point-inoculated with Fusarium graminearum under greenhouse conditions in two replicated experiments. Both general (GCA) and specific combining ability (SCA) were significant. Most of the variance for FHB severity was associated with additive genes; however, estimates for SCA ranged from highly negative to highly positive in both resistant × resistant and resistant × susceptible crosses which suggest that improving FHB resistance through gene pyramiding strategies based on additive genetic variation may be complicated by interaction effects that condition FHB resistance.     

Heterotic relationships among European maize inbreds

European flint maize (Zea mays L.)cannot be considered an uniform group of germplasm based on its origin and area of adaptation. However, maize breeders have not taken full advantage of the variability within the European flint germplasm. The objective of this work was to study the heterotic relationships among European maize inbreds from different origins. Nine European flint inbreds were crossed in a diallel that was evaluated in three environments in northwestern Spain. The variability within the European flint germplasm and the agronomic value of some inbreds could be utilized for maize breeding programs as an alternative to the systematic introduction of U.S. dent germplasm that is narrowing the germplasm base of breeding programs even in places where it is poorly adapted. Some European flint inbreds may also be valuable sources of earliness (F7 and EP42), resistance to root lodging (EA1070), and yield (EP42).These results suggest that, within the European flint germplasm, there could be some heterotic patterns, such as ‘north-central Europe × southern Europe’, which could provide an alternative to the heterotic pattern ‘European flint × U.S. dent’. This revised version was published online in August 2006 with corrections to the Cover Date.     

Production of Doubled Haploids by Anther Culture and Wheat X Maize Method in a Wheat Breeding Programme

Utilization of the doubled haploid method of breeding usually shortens the time to cultivar release, and methods of haploid production need evaluation in a breeding programme. Thirty-eight different three-way crosses were tested for anther culture response. On average 5.8 percent of the anthers cultured produced calli. Three crosses were found recalcitrant for callus induction. Overall, the anther culture method produced 0.6 plantlet per 100 anthers cultured. Five crosses with an average of 5.8 and 2.8 percent of anthers producing calli and plantlets, respectively, were compared using anther culture and wheat × maize crosses. Non-responsive genotypes for callus induction and plantlet formation in the anther culture method proved to be good parental material in wheat × maize crosses. The average percentages of embryo formation and plantlet production in wheat × maize crosses were 10.3 and 4.7, respectively. Anther-derived plants were cytologically unstable, whereas all the plants regenerated from wheat × maize crosses were haploids (n = 21 chromosomes). The chromosome numbers of the polyhaploids were doubled with a colchicine treatment. Improvement of the two haploid production methods to facilitate their efficient use in a breeding programme is discussed.     

我国玉米地方种质的单倍体诱导和加倍特性研究

双单倍体(doubled haploid,DH)育种技术具有加速育种进程的突出优势,已成为玉米育种关键性核心技术并在国外广泛应用.本试验选用47份玉米地方种质,进行单倍体诱导和单倍体加倍特性研究.结果表明,47份玉米地方种质材料之间杂交诱导的拟单倍体率有显著差异,介于1.64％～14.50％之间,平均为5.95％.种植12份玉米地方种质的拟单倍体籽粒进行田间鉴定,标记鉴定准确率介于40.2％～82.3％之间,校正单倍体诱导率介于2.33％～6.45％之间,表明玉米遗传背景影响到籽粒标记的表达,单倍体诱导率有明显差异.将15份玉米地方种质拟单倍体于冬季在海南田间种植,加倍授粉株率介于2.7％～27.2％之间,加倍结实株率介于0.7％～8.9％.说明我国玉米地方种质的遗传多样性丰富,单倍体诱导率和加倍率具有明显差异,利用DH育种技术可以拓宽和加强我国玉米地方种质在玉米育种中的利用.     

Relative efficiency of different Gramineae genera for haploid induction in triticale and triticale x wheat hybrids through the chromosome elimination technique

The study was undertaken to evaluate the relative efficiency of different Gramineae genera for haploid induction in triticale (x Triticosecale) and triticale × wheat (Triticum aestivum) hybrids through the chromosome elimination (wheat × maize, Zea mays) system. Eight intergenotypic triticale and 15 triticale x wheat crosses were subjected to hybridization with nine different Gramineae genera viz., Z. mays, Sorghum bicolor, Pennisetum americanum, Setaria italica, Festuca arundinacea, Imperata cylindrica, Cynodon dactylon, Lolium temulentum and Phalaris minor in two separate experiments. This was followed by in vivo auxin treatment of the crossed spikes and subsequent rescue of the haploid embryos to regenerate green haploid plantlets. All the triticale and triticale x wheat crosses resulted in seed set in variable frequencies when hybridized with maize, I. cylindrica, pearl millet and sorghum. Seed set was also obtained with S. italica, F. arundinacea and P. minor in a few crosses in both groups. In general, all the triticale x wheat crosses, except for one in each case, resulted in embryo formation and green haploid plantlet regeneration when hybridizations were carried out with maize and I. cylindrica. However, the latter outperformed the former in embryo formation (25.48% vs. 20.0%) and regeneration (34.17% vs. 15.10%) frequencies, the differences being significant for regeneration frequencies. In the case of triticale hybrids, no significant differences between maize and I. cylindrica were observed for the three parameters of haploid induction. Embryo formation and regeneration were also observed in some of the triticale as well as triticale × wheat F₁ hybrids when hybridized with sorghum and pearl millet.