**1. Introduction**

Bread wheat (*Triticum aestivum* L.) is a main crop with global importance for food safety and one of the major cereal source of nutrients for both humans and animals. This balance of consumption of required nutrient for human metabolic needs generally resulted in serious metabolic violations leading to sickness, poor health, suppressing of children development, and high economic expenses for society [1]. It is necessary for agricultural systems to ensure proper products, which will balance quantity of nutrients to support healthy life. However, in many developing countries, agriculture does not meet these requirements [2].

traits related to grain morphometry will be very important for feather genetic improvement

Mutant Resources of Spring Wheat to Improve Grain Quality and Morphology

http://dx.doi.org/10.5772/intechopen.75706

167

The grain protein content (GPC) is an economically valuable trait which plays one of the key roles in the determination of the wheat grain nutrition quality and has strong impact on the bread-making and end-use quality [15]. Despite the great importance of GPC, advancement in wheat breeding for high GPC is quite poor. One of the explanations of this situation is low variations by GPC among commercial cultivars; in addition, breeding for high GPC is very difficult and time consuming due to the trait complicated genetic control. The GPC is routinely screened in wheat breeding programs and selected the accessions with high protein content being for bread making and accessions with low protein content being for feed and other directions of industrial utilizations. One more limitation in wheat breeding programs for high GPC is the strong negative correlation between GPC and grain yield [16–18]. Nevertheless, it was shown that in common and spelt wheat populations, there are lines with simultaneous

The evidence of correlation between high GPC and grain morphometry such as grain size and grain shape has not been pointed out. The wild tetraploid wheat (*Triticum turgidum L. var. dicoccoides*) has gene for GPC as a promising source for wheat improvement [20], which is located on chromosome 6B [21]. The high protein content gene from *T. dicoccoides* has been transferred into hexaploid wheat [22]. However, the exclusive milling and baking properties of bread wheat are not found among the diploid and tetraploid wheats. Mainly because of the fact that only the hexaploid wheats have the subgenome D chromosomes derived from diploid *T. tauschii* which determine the quality parameters of bread making of common wheat as widely suggested by wheat scientists [23]. In order to improve the modern wheat cultivars by GPC characteristics without reductions in yield, it is very important to develop wheat genotypes with more high N-use efficiency which involves improved N-uptake and/ or N-remobilization [16]. The significant variations in GPC was related to post-anthesis N uptake independently of anthesis date and total N at anthesis [24, 25]. One of the last results on bread wheat highlights the correlation with GPC of post-flowering N uptake occurring

Iron and zinc deficiency is a widespread food-related health problem and affects over half of the world population [27, 28]. Wheat is the cheapest and primary source, which supplies the bulk of nutrients for the human diet. If compared to cultivated wheat species, the wild species appear to be a rich genetic resource for high Fe and Zn concentrations [29]. Meanwhile, despite cultivated wheat had mainly lower Fe and Zn concentrations that it was indicated for wild species, more their screening is required in order to find out elite germplasm with high Fe and Zn concentrations already possessing good agronomic productivity [30]. Wheat grain has low content micronutrients. For this reason, there is need for genetic enhancement with more of this nutrient being one of the most cost-effective and powerful method of diminishing

Biofortification of cereal grains is one of the most economic effective ways for solving the global micronutrients malnutrition issue. Biofortification has multiplicative advantages [31], and it is considered to be a promising and cost-effective approach for decreasing malnutrition

of wheat varieties according to their end-use quality demand.

high GPC and yield components [19].

early during grain development [26].

global micronutrients malnutrition [31].

and human health improvement [32].

Presently, over three billion people suffer due to micronutrient malnutrition and the numbers are increasing [3]. There are many human diseases associated with nutritional deficiency, and around two-thirds of all children's deaths are related to malnutrition [4, 5].

Improvement of many agronomic traits including grain quality requires their genetic variation, which should be separable from non-genetic impacts. Over the years, the main focus of wheat breeding programs was the replacement of traditional varieties with modern highyield ones that led to reduction of its genetic diversity mainly by end-use quality characteristics and nutrition quality (FAO Document Repository, 2015). The key desired traits for breeding were high yield and disease resistance. It is also known that the genetic variability of major crops currently have systematically decreased due to the repeated utilization of the local adapted genotypes in breeding processes which leads to the decreasing of the wide genetic recombination which may posse the novel traits [6].

Crops' genetic variability and therefore crop improvement could be powerfully generated through mutation breeding. Over the past 80 years, this approach has been applied for development of new mutant varieties of both seeds and vegetatively propagated crops [7–9]. According to the FAO/IAEA Mutant Variety Database, in 2014, there were 3220 mutant plant varieties of 214 plant species all round the world [10] (http://mvgs.iaea.org/). Application of mutagenesis in crop breeding has two main steps: the selection of individual mutants with improved traits after the mutagenic treatment and utilization of selected plants or lines in breeding programs [7].

One of the greatest contributions into crop yield is grain weight trait [11] which is directly related to two important morphometric characteristics such as grain size and grain shape. Grain size and grain shape are essential breeding traits because they are phenotypically the most stable of the yield components. They also greatly influence the grinding process, yield of flour, which is the main source for human consumption with a lot of other end-use utilizations, and starch damage [12]. Larger grains have strong contribution to higher grain weight in addition to increase in seedling vigor and production of dry matter of the raw material in the field [12, 13]. Grain size can be generally characterized by grain width (GW) and grain area (GA), however grain shape also determines along the grain′s main growth axis. Grain shape is measured by grain length (GL), grain width (GW), vertical perimeter, sphericity, and determination along the horizontal axis [12, 14]. It is very substantial to improve the wheat grain morphometry according to the demand of grain market and processing industries by various breeding approaches. Therefore, the estimation of genetic diversity of the traits related to grain morphometry will be very important for feather genetic improvement of wheat varieties according to their end-use quality demand.

**1. Introduction**

166 Global Wheat Production

breeding programs [7].

Bread wheat (*Triticum aestivum* L.) is a main crop with global importance for food safety and one of the major cereal source of nutrients for both humans and animals. This balance of consumption of required nutrient for human metabolic needs generally resulted in serious metabolic violations leading to sickness, poor health, suppressing of children development, and high economic expenses for society [1]. It is necessary for agricultural systems to ensure proper products, which will balance quantity of nutrients to support healthy life. However, in

Presently, over three billion people suffer due to micronutrient malnutrition and the numbers are increasing [3]. There are many human diseases associated with nutritional deficiency, and

Improvement of many agronomic traits including grain quality requires their genetic variation, which should be separable from non-genetic impacts. Over the years, the main focus of wheat breeding programs was the replacement of traditional varieties with modern highyield ones that led to reduction of its genetic diversity mainly by end-use quality characteristics and nutrition quality (FAO Document Repository, 2015). The key desired traits for breeding were high yield and disease resistance. It is also known that the genetic variability of major crops currently have systematically decreased due to the repeated utilization of the local adapted genotypes in breeding processes which leads to the decreasing of the wide

Crops' genetic variability and therefore crop improvement could be powerfully generated through mutation breeding. Over the past 80 years, this approach has been applied for development of new mutant varieties of both seeds and vegetatively propagated crops [7–9]. According to the FAO/IAEA Mutant Variety Database, in 2014, there were 3220 mutant plant varieties of 214 plant species all round the world [10] (http://mvgs.iaea.org/). Application of mutagenesis in crop breeding has two main steps: the selection of individual mutants with improved traits after the mutagenic treatment and utilization of selected plants or lines in

One of the greatest contributions into crop yield is grain weight trait [11] which is directly related to two important morphometric characteristics such as grain size and grain shape. Grain size and grain shape are essential breeding traits because they are phenotypically the most stable of the yield components. They also greatly influence the grinding process, yield of flour, which is the main source for human consumption with a lot of other end-use utilizations, and starch damage [12]. Larger grains have strong contribution to higher grain weight in addition to increase in seedling vigor and production of dry matter of the raw material in the field [12, 13]. Grain size can be generally characterized by grain width (GW) and grain area (GA), however grain shape also determines along the grain′s main growth axis. Grain shape is measured by grain length (GL), grain width (GW), vertical perimeter, sphericity, and determination along the horizontal axis [12, 14]. It is very substantial to improve the wheat grain morphometry according to the demand of grain market and processing industries by various breeding approaches. Therefore, the estimation of genetic diversity of the

many developing countries, agriculture does not meet these requirements [2].

around two-thirds of all children's deaths are related to malnutrition [4, 5].

genetic recombination which may posse the novel traits [6].

The grain protein content (GPC) is an economically valuable trait which plays one of the key roles in the determination of the wheat grain nutrition quality and has strong impact on the bread-making and end-use quality [15]. Despite the great importance of GPC, advancement in wheat breeding for high GPC is quite poor. One of the explanations of this situation is low variations by GPC among commercial cultivars; in addition, breeding for high GPC is very difficult and time consuming due to the trait complicated genetic control. The GPC is routinely screened in wheat breeding programs and selected the accessions with high protein content being for bread making and accessions with low protein content being for feed and other directions of industrial utilizations. One more limitation in wheat breeding programs for high GPC is the strong negative correlation between GPC and grain yield [16–18]. Nevertheless, it was shown that in common and spelt wheat populations, there are lines with simultaneous high GPC and yield components [19].

The evidence of correlation between high GPC and grain morphometry such as grain size and grain shape has not been pointed out. The wild tetraploid wheat (*Triticum turgidum L. var. dicoccoides*) has gene for GPC as a promising source for wheat improvement [20], which is located on chromosome 6B [21]. The high protein content gene from *T. dicoccoides* has been transferred into hexaploid wheat [22]. However, the exclusive milling and baking properties of bread wheat are not found among the diploid and tetraploid wheats. Mainly because of the fact that only the hexaploid wheats have the subgenome D chromosomes derived from diploid *T. tauschii* which determine the quality parameters of bread making of common wheat as widely suggested by wheat scientists [23]. In order to improve the modern wheat cultivars by GPC characteristics without reductions in yield, it is very important to develop wheat genotypes with more high N-use efficiency which involves improved N-uptake and/ or N-remobilization [16]. The significant variations in GPC was related to post-anthesis N uptake independently of anthesis date and total N at anthesis [24, 25]. One of the last results on bread wheat highlights the correlation with GPC of post-flowering N uptake occurring early during grain development [26].

Iron and zinc deficiency is a widespread food-related health problem and affects over half of the world population [27, 28]. Wheat is the cheapest and primary source, which supplies the bulk of nutrients for the human diet. If compared to cultivated wheat species, the wild species appear to be a rich genetic resource for high Fe and Zn concentrations [29]. Meanwhile, despite cultivated wheat had mainly lower Fe and Zn concentrations that it was indicated for wild species, more their screening is required in order to find out elite germplasm with high Fe and Zn concentrations already possessing good agronomic productivity [30]. Wheat grain has low content micronutrients. For this reason, there is need for genetic enhancement with more of this nutrient being one of the most cost-effective and powerful method of diminishing global micronutrients malnutrition [31].

Biofortification of cereal grains is one of the most economic effective ways for solving the global micronutrients malnutrition issue. Biofortification has multiplicative advantages [31], and it is considered to be a promising and cost-effective approach for decreasing malnutrition and human health improvement [32].

The aims of present studies were: (1) to generate M<sup>5</sup> mutant lines of spring common wheat in genetic background of cv. Eritrospermum-35; (2) to evaluate variability in components of productivity, including grain number and weight per main spike (GNS and GWS), grain weight per plant (GWP) and 1000-grain weight (TKW), variability in grain morphometry (size and shape), and quality parameters, namely GPC, grain Fe (GIC), and grain Zn (GZnC) concentrations in parent and M5 mutant lines from generation developed by irradiation treatment of seeds with 100 Gy and 200 Gy and identify those that have high-yield characteristics and improved grain quality traits; and (3) to estimate relationship between two sets of data, including grain quality and agronomic performance parameters.

**2.2. Grain morphometric analysis**

line and the GL:GW ratio was also calculated.

grain samples (100-Gy- and 200-Gy-dosed M5

performed.

**2.4. Statistical analysis**

statistically significant.

**3. Results and discussion**

the parent up to 5.7–11.0% GPC higher.

of 13.62 ± 0.60% (**Figure 1**). It identified 11 advanced M<sup>5</sup>

Morphometric analysis was performed with the WinRHIZO and image analysis system ((version 1.38 2007, Reagent Instruments Inc., Canada) for GL, GW, and GA on 50–60 grains per

Grain protein content was estimated with near infrared reflectance (NIR) spectroscopy of whole grains (ZX50 Portable Grain Analyzer, USA) using respective calibration software pro-

The measurements of grain iron and zinc concentrations were described in detail [33]. Briefly,

washed with sodium dodecyl sulfate (0.1%) with the following several times washings in deionized water, dried, ground with a mixer mill (Retsch MM400 GmbH) and digested (0.2 g) with a mixture of nitric acid (65%, analytical grade) and hydrogen peroxide (30%) (5:1, v/v) using digestion automat K-438 and scrubber K-415 model triplescrub (BÜCHI Labortechnik AG CH-9230 Flawil 1/Switzerland). The sample was diluted to 20 mL with twice-distilled water. The Fe and Zn concentrations were analyzed using flame atomic absorption spectroscopy (Analytic Jena NovAA350, Germany). Estimation of mineral nutrients were checked against the certified reference values from the State standard samples LLC "HromLab," Zn 7837–2000, Fe 7835–2000 diluted by 0.3% HNO3. Three extracts and analysis repetitions were

All data were evaluated in R 3.0.2 (R Core Development Team 2013). The simultaneous tests of general linear hypotheses, Dunnett Contrasts, were used for multiple comparisons of the means. Summarized data are reported as a mean values ± standard deviations. Correlation coefficients between productivity components and grain-quality parameters and *p* values were calculated using the GenStat software (10th edition). A *p*-value ≤0.05 was considered

In the current study, GPC showed considerable variation from 12.60 to 14.73% with a mean

were from 100-Gy gamma-irradiated lines, which demonstrated significant differences from

The screening of mutant lines (*n* = 90) for Fe concentration (GIC) showed great variations in this grain quality parameter (**Figure 2**). The GIC varied from 13.49 to 65.53 mg/kg with a mean

mutant lines and cv. Eritrosperumum-35) were

Mutant Resources of Spring Wheat to Improve Grain Quality and Morphology

http://dx.doi.org/10.5772/intechopen.75706

169

mutant lines (37.7%), of which 5 lines

**2.3. Estimation of grain protein content, iron and zinc concentrations**

vided by Zeltex. Three repetitions were studied using 25 grains per line.
