Can Technological Development Compensate for the Unfavorable Impacts of Climate Change? Conclusions from 50 Years of Maize (Zea mays L.) Production in Hungary

The goals of our study were to evaluate the historical aspects of maize (Zea mays L.) production in Hungary, and to provide a prognosis for the yield for 2050 based on the trends of temperature, precipitation, and climatic water balance changes. Different climate zones for the period of 1970–2019 were investigated by means of correlation analyses, normality tests, time series analysis, and multiple linear regression analysis. Two well-distinguishable linear trends in the yields were found, the first representing large-scale farming, and the second starting with the change of the socio-economic system in 1989. The annual amount of precipitation showed high variations both spatially and temporally, although no significant change was identified for the last five decades. In the period 1990–2019, not only were higher temperatures characteristic, but the frequency of extreme high temperature values (Tmax > 30 °C) also increased. We quantified the heat stress, expressing it in heat stress units (HSU, °C) derived from the heat-sum of the daily maximum air temperature values above 30 °C. By 2050, the average increase in HSUs may reach 35 °C. Increasing HSU causes yield depression; according to our estimations, a 1 °C increase in HSU results in a 23 kg ha−1 yield depression of maize. Taking the unfavorable effect of heat stress and technological development into consideration, the average domestic yield of maize will be 8.2 t ha−1. Our study revealed that without taking technological development into consideration, prediction models may overestimate the adverse effect of climate change on crop production.

Zinc and amino acids impact on nutrient status of maize during the ‘critical window’

It has been assumed that zinc (Zn) fertilizers applied to maize simultaneously with amino acids (AA) at early stages of its growth may decrease the yield variability due to correcting its nutritional status during the ‘critical window’. Two Zn carriers were evaluated (Zn-I – Zn chelate; Zn-II – Zn oxide); they were applied to maize at BBCH 14/15 with or without amino acids, based on two rates of nitrogen (80 and 160 kg N/ha). The precipitation deficiency in 2015 resulted in the grain yield decrease by 35% compared to 2014. An advantage of higher N rate was proved in 2014, whereas the influence of Zn and AA showed in 2015. In this year, the beneficial impact of Zn-oxide and AA combined application resulted in amelioration, at least partially, of the imbalance of certain macronutrient content (N, P, Mg) during the ‘critical window’. These effects were revealed due to a boosted number of kernels in cob, and particularly higher thousand kernel weight. Consequently, the yield depression in 2015 was partly overcome. The results indicated that simultaneous application of Zn oxide and AA to maize at BBCH 14/15 corrected both its nutritional status during the ‘critical window’ and yield components, but had no effect on the yield itself.

The effect of water supply and crop year on the yield potential of sweet maize (Zea mays L. convar. saccharata Koern.) hybrids with different genotypes

The successfulness of crop production is significantly affected by not only the the average yields that provide cost effectiveness, but also the success of striving for yield safety, therefore, varieties and hybrids tolerant to environmental stress factors are worth being included into the sowing structure. Our aim was to further the decision making of producers in prepaering the right sowing structure by the evaluation of sweet maize hybrids’ tolerance to excess rainfall.We performed our examinations in an extremely wet year (2010) on chernozem soil on three sweet maize hybrids (GSS 8529, GSS 1477, Overland) in 12 replications. Comparing the yields of 2010 with those that can be expected under optimal rainfall conditions, we showed that the examined hybrids react to the amount of rainfall higher than their needs with yield depression. The excess rainfall tolerance of the examined hybrids is different in the case of each hybrid.

Impacts of soil and groundwater salinization on tree crop performance in post-tsunami Aceh Barat, Indonesia

The Indian Ocean tsunami of December 2004 had far reaching consequences for agriculture in Aceh province, Indonesia, and particularly in Aceh Barat district, 150 km from the seaquake epicentre. In this study, the spatial distribution and temporal dynamics of soil and groundwater salinity and their impact on tree crops were monitored in Aceh Barat from 2006 to 2008. On 48 sampling points along ten transects, covering 40 km of coastline, soil and groundwater salinity were measured and related to mortality and yield depression of the locally most important tree crops. Given a yearly rainfall of over 3000 mm, initial groundwater salinity declined rapidly from over 10 to less than 2 mS cm−1 within two years. On the other hand, seasonal dynamics of the groundwater table in combination with intrusion of saline water into the groundwater body led to recurring elevated salinity, sufficient to affect crops. Tree mortality and yield depression in the flooded area varied considerably between tree species. Damage to coconut (65% trees damaged) was related to tsunami run-up height, while rubber (50% trees damaged) was mainly affected by groundwater salinity. Coconut yields (−35% in average) were constrained by groundwater Ca2+ and Mg2+, while rubber yields (−65% on average) were related to groundwater chloride, pH and soil sodium. These findings have implications on planting deep-rooted tree crops as growth will be constrained by ongoing oscillations of the groundwater table and salinity.

The Effect of High Concentrations of Glufosinate Ammonium on the Yield Components of Transgenic Spring Wheat (Triticum aestivumL.) Constitutively Expressing thebarGene

We present an experiment done on abar+wheat line treated with 14 different concentrations of glufosinate ammonium—an effective component of nonselective herbicides—during seed germination in a closed experimental system. Yield components as number of spikes per plant, number of grains per spike, thousand kernel weight, and yield per plant were thoroughly analysed and statistically evaluated after harvesting. We found that a concentration of glufosinate ammonium 5000 times the lethal dose was not enough to inhibit the germination of transgenic plants expressing thebargene. Extremely high concentrations of glufosinate ammonium caused a bushy phenotype, significantly lower numbers of grains per spike, and thousand kernel weights. Concerning the productivity, we observed that concentrations of glufosinate ammonium 64 times the lethal dose did not lead to yield depression. Our results draw attention to the possibilities implied in the transgenic approaches.

Influence of weed infestation on morphological parameters of maize (Zea mays L.)

The influence of various ways of regulation in weed infestation of silage maize stands was studied in 1999–2001. Four variants of stands were compared: 1. without weed eradication (check), 2. mechanically weeded throughout the whole vegetation period, 3. mechanically weeded from the beginning of vegetation till the phase of 5^th leaf and later on without protection, 4. chemical weeding. The yield of dry mass and morphological characters (height of plants, stem diameter, number of ears per plant etc.) show the substantial negative effect of weed infestation upon the studied parameters. The yield from the check variant reached 8.09 t/ha, from the 2^nd variant 13.24 t/ha, from the 3^rd variant 11.46 t/ha and from the 4^th variant 12.34 t/ha. The decrease of mass in individual parts of plants were observed but their percentage portions were not affected by the level of weed infestation. A high dependence ( = 0.01) between the mass of the whole plant and the ear mass (r = 0.98) was proved. The total number of leaves was not affected by the level of treatment. The results show that the mechanical cultivation of stands at the beginning of vegetation cannot prevent the yield depression cost by weed infestation and the studied parameters cannot reach the level of fully weeded variants.

Heritability of Yield and Secondary Traits in two populations of Para Rubber Tree (Hevea brasiliensis)

Heritability and interactions of yield and growth traits were assessed in Hevea brasiliensis using full-sib progenies and clonal populations. Using parent-offspring regression, annual mean rubber yield (ARY) and summer yield (SY) showed moderate to high heritability (ARY, h2 =34–56%; SY, h2 =36–52%). Among the yield components, girth exhibited low to moderate heritability (h2 =17–36%) while branching height showed low heritability (h2 =18%). Using forty clonal genotypes, annual mean rubber yield (H2=48%), rubber yield during peak period (H2=47%) and rubber yield during stress (or summer yield) (H2=44%) showed high estimates of heritability. Among the other yield components, except volume of latex during stress period (H2=40%), remaining yield components showed moderate estimates for heritability (H2=29–37%). Dry rubber content (DRC) based on annual mean showed very high heritability (H2=68%), followed by DRC during stress (H2=51%) and peak (H2=50%) periods. Latex flow rate based on annual mean and peak period data showed high heritability (H2=51%) followed by latex flow rate during stress period (H2=42%). Plugging indices of annual and stress period showed high heritability (H2=43%) than that of peak period (H2=25%). Regarding growth traits, girth showed high heritability (H2=50%) than girth increment (H2=32%). While bark thickness showed high heritability (H2=40%) length of tapping panel showed moderate heritability (H2=27%). Total chlorophyll content exhibited moderate heritability (H2=22%); chlorophyll pigment ratio showed low heritability (H2=5%). Based on parent-offspring analysis, annual mean rubber yield exhibited high genetic correlation with summer yield and girth. Annual mean rubber yield and summer yield were negatively correlated with branching height. Regarding phenotypic correlations among the forty clonal genotypes, annual mean rubber yield exhibited high correlation with latex volume, latex flow rate, DRC, girth and bark thickness. However, annual mean rubber yield was negatively correlated with yield depression under stress and plugging index. Rubber yield, volume and rate of flow of latex over the three periods, yield depression under stress, girth increment, annual mean plugging index and plugging index under stress showed high estimates of genetic advance. The high estimates of heritability for yield and its components coupled with their high genetic gain indicated that considerable improvement can be achieved for these traits through selection. Estimates for indirect selection efficiency were not optimal for indirect selection for yield using girth and summer yield.