Effects of triticale cultivars grown in a Mediterranean environment on biomass yield and quality

Triticale is a valuable crop in Mediterranean environments because its growth capacity at low temperatures and its precocity make it possible to obtain high biomass yields in early spring. Precocity of triticale is particularly appreciated in Mediterranean environment, where irrigation allows the sowing of a spring–summer corn crop after a winter cereal crop has been harvested for silage. In these conditions, early planted corn can take advantage of both longer-cycle cultivars and of the lower incidence of the European corn borer Ostrinia nubilalis attacks. Nutritional quality of triticale as forage is related to the phenological stage at harvest, cultivar choice, seeding rate and environmental conditions. The work reported in this paper was aimed at verifying if the hypothesized effects of the different habitus (cold requirement) of triticale cultivar grown at different seeding rates affect biomass quantity and quality at the stages of flowering and milk-waxy-maturity, which are the most relevant for triticale silage production

Genetic variation for the duration of pre-anthesis development in durum wheat and its interaction with vernalization treatment and photoperiod

A recombinant inbred durum wheat population was grown under three contrasting regimes: long days following vernalization (LDV), long days without vernalization (LD), and short days following vernalization (SDV). The length of several pre-anthesis stages and the number of leaves and the phyllochron were measured. Different groups of genes were involved in determining the phenology in the three treatments, as demonstrated by a quantitative trait locus (QTL) analysis. The length of the period required to reach the terminal spikelet stage was correlated with the time to anthesis only in the case of LDV- and LD-grown plants where the timing of anthesis depended on the final leaf number. However, for SDV-grown plants, anthesis date was more dependent on the length of the period between the terminal spikelet stage and anthesis and was independent of leaf number. The involvement of the phyllochron in determining the duration of pre-anthesis development was also treatment-dependent. QTL mapping of the various flowering time associated traits uncovered some novel loci (such as those associated with the phyllochron), in addition to confirming the presence of several well-established loci

Modelling potential maize yield with climate and crop conditions around flowering

Abstract Understanding, and then modelling, the effects of sowing date and cultivar on maize yield is essential to develop appropriate climate change adaptation strategies. Here we test the WOFOST model and a hybrid model, based on physiological crop conditions around flowering, against observed data collected during 4 years of field experiments in a Mediterranean environment under fully irrigated conditions. We simulate sowing date and cultivar responses by using 45-year historical meteorological records from the experimental weather station and future climate conditions till 2060 as projected by a set of regional climate models. Both WOFOST and the hybrid approach reveal good performance in simulating average maize yield. However, the hybrid one outperforms WOFOST with respect to its responsiveness to changes in sowing date and cultivar. These findings, besides stressing the importance of crop conditions around flowering in determining maize yield, point to lower yields (14 %–17 %, average reduction) under future climate conditions. The estimated losses may only be partially offset by changes in phenology and sowing dates

Sowing rate and cultivar affect total biomass and grain yield of spring triticale (&#xd7;<i>Triticosecale</i> Wittmack) grown in a Mediterranean-type environment

Sowing rate and cultivar are basic management choices affecting biomass production, grain yield and forage quality of triticale, but their effect on this species has seldom been analysed through explanatory models such as grain yield = radiation intercepted (RI) X radiation use efficiency (RUE) X harvest index (HI). A 3-year field experiment was carried out in Sardinia (Italy) to explain the effect of five sowing rates (50, 100, 300, 500 and 700 germinable seeds per unit area) and of two cultivars of contrasting height on above-ground dry matter (AGDM) and grain production under both rainfed and irrigated conditions. The different sowing rates applied were effective in determining different plant numbers per unit area, although in 1994 the plant population density was lower than expected. Increasing sowing rates caused faster development, with a 1-week difference between extreme sowing rates in time to achieve double ridge and terminal spikelet. AGDM at anthesis was small or not influenced by sowing rate, due to the small differences in RI deriving from the greater LAI of the highest sowing rates (an average of 2.4 for 300, 500 and 700 versus 1.8 of 50 and 100). AGDM accumulated after anthesis increased as a consequence of increasing the sowing rate from 50 to 300, causing parallel differences in AGDM at maturity (from 1550 to 2177 g m&#x00AF;2 on average) and in grain yield (from 524 to 781 g m&#x00AF;2 on average). The greater AGDM accumulated after anthesis by 300 and 700 was due to a greater RI in 1996, but to a greater RUE in 1995, when a notable difference in sink size among sowing rates was detected. Sink size was also responsible for the higher HI observed at the highest population densities in two seasons out of three. The superiority of cultivar Rigel in AGDM production derived from its higher RUE (1.26 versus 1.04 g MJ&#x00AF;1 of Antares), associated with a lower specific leaf area and with a better light distribution within the canopy. The latter was a consequence of a lower radiation extinction coefficient before ear emergence (0.60 versus 0.70), and of less radiation intercepted by Rigel ears afterwards. A higher HI allowed the greater AGDM produced by Rigel to be translated into a higher grain yield in 2 years out of three, in spite of Rigel being taller. The framework used was effective in explaining the differences in AGDM and grain yield induced by the treatments applied. RUE was not affected by the different LAIs realised before anthesis, but was sensitive to variations in the sink capacity in the post-anthesis period and to differences in canopy structure between cultivars

The Effect of breeding on the phenology of Italian durum wheats: from landraces to modern cultivars

An understanding of the changes in phenology resulting from durum wheat breeding in Italy can inform breeding objectives for durum wheat improvement in Mediterranean environments. The phenology of a set of 20 durum wheat cultivars, grouped according to their period of release into ‘old’, ‘intermediate’ and ‘modern’, was compared in two sowings (September and May) with or without artificial vernalization. The vernalization treatment and the 6 h range in daylength and wide variation in temperature were responsible for the variation in anthesis date from 817 to 2105 °Cd (base 0 °C) from sowing. Old cultivars had the greatest photoperiod sensitivity and cold requirement, intermediate ones the greatest earliness >per se and modern ones the least photoperiod sensitivity and greatest earliness per se. The first substantive effect of breeding in Italy on phenology was achieved with introgression from syriacum germplasm, which increased earliness both by an increase in earliness per se and a reduction in photoperiod sensitivity. The next step, characterized by the introduction of the semi-dwarfing gene Rht1, had a specific effect of reducing photoperiod sensitivity, although the modern group of varieties has a relatively low level of earliness per se, which is fundamental for preserving and increasing the length of the TS-anthesis period. Some quantitative cold requirement still persists in Italian germplasm, although all the cultivars tested are classified as spring types. The main phenological events affected by the changes in anthesis date resulting from breeding depend on the mechanism involved. Variability among cultivars within each group is also described

Grain yield, dry matter, and nitrogen accumulation in the grains of durum wheat and spring triticale cultivars grown in a Mediterranean environment

Comparisons among species can be a valuable approach to identifying traits important for plant breeding. Differences between 2 durum wheat (Duilio and Creso) and 1 triticale (Antares) cultivar have been analysed in a 2-year field trial in Sardinia (Italy), in order to define a more productive durum wheat ideotype for Mediterranean-type environments. The greater grain yield (569 v. 447 g/m2) and the lower protein percentage (9.2 v. 10.6%) of triticale cv. Antares compared with the durum wheat cultivars, at a similar level of biomass produced at heading, were analysed in terms of number of grains per unit surface and rate and duration of dry matter (DM) and nitrogen (N) accumulation, calculated from a logistic curve. When the single grains were considered, Antares showed a lower rate but a longer duration of DM and N accumulation in the more favourable season, resulting in lower DM (40 v. 54 mg) and N (0.7 v. 1.0 mg) contents in the grain. On the other hand, when data were expressed on a per unit surface basis, the greater spike fertility of Antares (53 v. 39 grains per spike) and its longer duration of accumulation, were responsible for similar or even greater amounts of DM and N accumulated in the grains per m2. Growth rate of single grains, although able to explain differences in single grain weight, cannot explain differences in grain weight per m2 and hence in yield, which mainly result from variation in the number of grains per spike. Nitrogen percentage of the grains decreased from the maximum values observed at the beginning of grain filling, until a constant final value attained before the end of DM and N accumulation. Rate is more important than duration in determining the quality characteristics of grains, as higher grain weights and protein percentages correspond to higher rates of DM and N accumulation

Awnedness affects grain yield and kernel weight in near-isogenic lines of durum wheat

The importance of awns in durum wheat (Triticum turgidum L. var. durum) has to be evaluated whenever an increase in grain yield is expected due to a greater photosynthetic capacity of the awned ear. Awned and awnless isolines of durum wheat were compared in a 3-year field trial in Sardinia (Italy). Ear and flag-leaf size, radiation interception, canopy temperature, yield, and yield components were measured. Awns increased the ear surface area from 36 to 59%, depending on their length, which ranged from 5.5 to 13.8 cm. This resulted in an average 4% more radiation intercepted by the awned ears. Canopy temperature was 0.9°C lower, on average, in the awned isolines, and was negatively correlated with kernel weight (r = &#8211;0.85**, n = 10), although consistent and marked effects of awns on canopy temperature were only observed in the long-awned lines. Awns positively affected grain yield, with an average increase of 10 and 16%, respectively, in the 2 years in which they affected kernel weight. The irrelevant effect of awns on yield in the year characterised by a severe drought was a consequence of their early desiccation. The effects of awns on grain yield and kernel weight strongly depend on the genetic background, on awn length and functionality, and on the environmental conditions during grain filling

Relationships between grain-filling parameters, fertility, earliness and grain protein of durum wheat in a Mediterranean environment

Seven Italian durum wheat (Triticum turgidum L. var. durum) cultivars characterized by different height, time to anthesis, fertility and kernel weight were compared under different moisture levels and soil types in two experiments. Duration, and maximum and average rate of grain-filling (GF) were estimated from 2nd and 3rd order polynomials, regressing kernel weight on growing degree days (GDD, base temperature 9&#xb0;C). In both experiments Messapia was the earliest cv, flowering between 132 and 139 days after sowing (das), and Vespro and Creso the latest, flowering between 141 and 148 das. The largest kernels, ranging between 51.8 and 59.5 mg, were always realized by these three cultivars and were always associated with the highest rates of GF. Average rates ranged from 105 to 152 &#x3bc;g &#xb0;C day&#x2212;1 and were significantly correlated, both environmentally and phenotypically, with maximum kernel weight. Maximum rates of GF, ranging from 172 &#x3bc;g &#xb0;C day&#x2212;1 in the genotype D3415 to 282 &#x3bc;g &#xb0;C day&#x2212;1 in cv Creso, were only phenotypically correlated with maximum kernel weight. GF duration was related to earliness as it ranged from a minimum of 380 GDD in the late cv Vespro, to a maximum of 481 GDD in the earliest cv Messapia. Fertility varied greatly, from 37 kernels per spike in Creso and Vespro, to 61 kernels per spike in Vespro. Significant differences in grain protein were recorded between cultivars (8.9% in Karel to 15.8% in D3415) and soils (10.8% and 14.1%). In this environment, large kernels can be achieved with genotypes characterized by high rates of GF, irrespective of earliness, and without negative effects on spike fertility and on grain protein content

The Response of rate and duration of grain filling to long-term selection for yield in Italian durum wheats

Genetic advance in durum wheat (Triticum turgidum subsp. durum) grain yield in Italy has been achieved by bringing forward flowering time, achieving a larger number of grains per unit area, and altering the pattern of senescence. The performance, in the absence of any moisture stress, of a set of 6 Italian durum wheat cultivars released over the past 100 years was compared under 4 environments and 2 nitrogen rates, to ascertain whether the changes brought about by selection for yield have also indirectly affected the rate and duration of grain filling. Grain filling lasted 35–36 days in all cultivars except ‘Ichnusa’ (39 days), although modern cultivars flowered earlier than older ones. The lack of any breeding effect on grain-filling duration also meant that the later old cultivars were not negatively affected by the higher ambient temperatures during their grain filling. The maximum rate of grain filling ranged from 2.4 to 3.3 mg/day and showed a highly significant negative correlation with the year of cultivar release (r = –0.91*). The variation in grain weight, significant but not correlated with the year of release, was associated with the rate of grain filling, which was in turn related to the grain number per unit area. A compensating variability still exists among modern Italian cultivars in both grain number and grain-filling rate, which demonstrates that durum wheat grain yield can be increased while also preserving high grain weights

The Effect of nitrogenous fertiliser application on leaf traits in durum wheat in relation to grain yield and development

Nitrogen (N) fertilisation boosts the grain yield of wheat through its influence on yield components, phenology and leaf traits. Both crop growth and senescence are dependent on N supply, as are the number of kernels set per unit area and per ear, and the mean kernel size. A two-season trial of four semi-dwarf durum wheat cultivars, grown at two levels of N, was used to illustrate the effects of N on canopy temperature, leaf resistance and flag leaf senescence pattern under irrigated conditions in a Mediterranean climate, and to explore the consequences of these effects on the crop phenology, its yield and its yield components. The well-fertilised crop developed a larger leaf area index at anthesis and a lower leaf resistance, thus generating a lower canopy temperature and delayed anthesis. Its grain fill duration was shorter, in spite of its lower canopy temperature, presumably because the increased N availability resulted in the development of a stronger sink (more kernels per unit area and per ear), which was associated with earlier senescence, thereby shortening the duration of grain fill, and led to reduced kernel weight