Issue 4 (188)/2021

ALSE and ACS Style
Plăcintă, D.; Murariu, D. Study of phenotypic variability using the varietal diversity of cultivated forms of naked and hulled oats in the intercropping system. Journal of Applied Life Sciences and Environment 2021, 54(4), 389-404.
https://doi.org/10.46909/journalalse-2021-034 

AMA Style
Plăcintă D, Murariu D. Study of phenotypic variability using the varietal diversity of cultivated forms of naked and hulled oats in the intercropping system. Journal of Applied Life Sciences and Environment. 2021; 54(4): 389-404.
https://doi.org/10.46909/journalalse-2021-034 

Chicago/Turabian Style
Plăcintă, Domnica, and Danela Murariu. 2021. “Study of phenotypic variability using the varietal diversity of cultivated forms of naked and hulled oats in the intercropping system” Journal of Applied Life Sciences and Environment 54, no. 4: 389-404.
https://doi.org/10.46909/journalalse-2021-034 

Study of Phenotypic Variability Using the Varietal Diversity of Cultivated Forms of Naked and Hulled Oats in the Intercropping System

Domnica Plăcintă^1*, Danela Murariu¹

¹Plant Genetic Resources Bank “Mihai Cristea” Suceava, Romania 

*E-mail: domnica_p@yahoo.com 

Received: Mar. 02, 2022. Revised: Mar. 15, 2022. Accepted: May 08, 2022. Published online: May 30, 2022

ABSTRACT. The research carried out at the Gene Bank in Suceava, Northern Romania, aimed to highlight the phenotypic variability of the germplasm of Avena spp. For this purpose, the morpho-productive traits and resistance to diseases, pests and weeds were analysed. Productivity, diseases and pests, days to heading and days to maturity descriptors of 46 Avena spp. genotypes (naked and hulled oat) with different biological statuses (36 local populations, 10 cultivars), were evaluated by testing in intercropping experiments with small grain cereals and grain legumes. The unidirectional ANOVA analysis generated values that allowed the elaboration of a hierarchy of heterogeneity in the hulled local populations, for some of the analysed characters (one thousand seeds weight/genotype, degree of attack by Puccinia coronata and Oulema melanopa and days to maturity) and these were less in naked forms. There was a high competition of Avena species, regarding weeds in small grain cereal variants and potentially beneficial for nitrogen symbiotic fixation by increasing naked and hulled local oat population productivity in intercropping with fava bean. The Euclidean distance classification of the oat genotypes investigated in the dendrogram distinguished the generated groups, indicating the maximum distance in cluster IV. With high heterogeneity of productivity traits, better resistance to disease and pests, and shorter maturity, members of this cluster could be used to develop genetic mixture programs.

Keywords: phenotypic variability, morphological traits, intercropping, naked and hulled cultivars.

INTRODUCTION

The existence of genetic resources in gene banks has focused mainly on conservation aspects, but in the context of climate change, the sustainability of agriculture there is an urgent need to involve under-used genetic stocks with defined traits (local populations, crop wild relatives) to exploit the potential value for the benefit of society (ECPGR, 2010). This includes adapting local populations to new management systems and establishing a mixed system of selection between farmers and breeders using the technology available for the development of evolved local breeds (Casanas et al., 2017).

Because of an increase in nutrient usage efficiency and – in the case of legume-cereal combinations – nitrogen transfer, it was discovered that under low-input conditions intercropping systems can provide greater yields than monocropping systems (McLaughlin and Mineau, 1995; Ruijven and Berendse, 2003).

In interspecific diversity, oats (Avena L.) is one of the old cereal genres with many wild species and few cultivated forms, including diploid (Avena strigosa Screb), tetraploid (Avena abyssinica Hochst), hexaploid (Avena sativa ssp. sativa L., Avena sativa ssp. nudisativa (Husn.) Fruit. et Sold., Avena byzantina C.K. (Loskutov et al., 2005) used in some regions of the globe for animal feed and human nutrition.

The study was conducted to identify genetic mixtures in order to improve the quality of agroecosystems and preserving biodiversity.

MATERIALS AND METHODS

The study was made on 46 genotypes from different oat species and biological status (25 samples of the hulled local populations, 11 samples of the naked local populations, 4 samples of the hulled cultivars, 6 samples of the naked cultivars) tested in intercropping with two species (Vicia faba and Hordeum vulgare). The oat genotypes tested are from the Suceava Gene Bank collection with origins in Romania and other European countries belonging to the species of oats hulled (Avena sativa ssp. sativa, Avena byzantina, Avena strigosa, Avena abyssinica) and naked (Avena sativa ssp. nudisativa, Avena sativa ssp. nudisativa var. inermis, Avena sativa ssp. nudisativa var. chinensis) (Table 1).

Table 1
Biological material tested

Table 2
The experimental design for intercropping system

Legend: HLP – hulled local population, NLP – naked local population, HAC – hulled cultivar, NAC – naked cultivar.

The experimental design for intercropping system (Table 2) was accomplished in 2 blocks with 46 plots, in consecutive order (1 – 46). Each plot had 6 rows of 1.5 m length labelled thus: plot 1 (V₁ – 2 rows Avena spp., V₂ – 1 row Avena spp., 1 row Vicia faba, V₃ – 1 row Avena spp., 1 row Hordeum vulgare), plot 2 (V₁, V₂, V₃) … to the plot 46 (V₁, V₂, V₃).

In the intercropping oat with fava bean and barley, there were no chemical treatments, and manual ploughing was carried out.

The estimation of the phenotypic variability was made based on the specific morpho-physiological descriptors: yield/ genotype, 1000 seed weight, degree of attack of foliar diseases: Septoria leaf blotch (Septoria avenae f. sp. avenae %), crown rust (Puccinia coronata f. sp. avenae %), degree of attack of oat leaf beetle (Oulema melanopa %) on plants, days to heading, days to maturity. In order to evaluate the behaviour of Avena spp. in terms of competition with weeds species, their distribution was determined and studied in each variant.

The main climatic parameters of the two years of study were similar in terms of temperature, but the precipitation differed a lot in April (31.2 mm), May (33.9 mm) and July (21.1 mm), the difference being of 63.6 mm throughout the vegetation period of the oats (Table 3).

Table 3
Air temperature and rainfall during the growing season

Statistical analyses

For all mentioned descriptors were calculated average (x), variation amplitude (min-max), F-ANOVA test (p/0.05), and LSD test (p/0.05) using SPSS 26.

RESULTS AND DISCUSSION

Tests performed on the studied oat germplasm showed a clear differentiation of the productivity traits. The average values obtained highlighted the high yield genotype that was recorded in variant V₂ in 2019 for hulled (91.73 g/m) and naked local populations (69.21 g/m) (Table 4). Due to the small amounts of rainfall from May to June (85.0 – 140.1 mm; Table 1) in the phenophases of elongation of the straw and flowering-heading low average values of the yield/genotype were noticed in 2020, in hulled local populations (49.11 g/m) and naked local populations (20.5 g/m) compared to 2019, an aspect also specified by Bîlteanu G. et al. 1991.

In addition, in the two years of testing, the one-thousand-seeds weight as a productivity element showed a greater variation of the average values and amplitudes (min-max) within the oat hulled local populations, in comparison with the naked ones (Table 4). The hydric stress in April of 2020 (5.4 mm) during the emergence period and in June (140.1 mm) during the flowering-heading phenophase determined in the case of hulled local populations a variable number of seedlings with a large number of inflorescences and kernels with a lower degree of grain roundedness (average/2020; V₁ – 28.48, V₂ – 25.12; V₃ – 23.92) compared to 2019 (average; V₁ – 31.30, V₂ – 30.32; V₃ -30.80).

The ANOVA F factor, emphasises significantly high values (Table 4) statistically differentiating local hulled populations by naked local populations through a high heterogeneity of productivity traits (one-thousand- seeds weight/genotype, F (2, 72) – 8.346) in the all variants by 2020. The LSD test values show statistically significant differences in the hulled local populations for the one-thousand-seeds weight/genotype between the three types of variants (V_1, V₂, V₃), (p-0.000*).

Regarding the susceptibility to Puccinia coronata, average values of 3.52 in V₁ and 0.60 in V₂ for hulled genotypes and average values of 3.27 in V₁ and 0.09 in V₂ for naked genotypes compared to the V₃ variant where both genotypes were immune, were observed in 2020.

In the 2020 intercropping system, the ANOVA F factor highlighted a large variation in the degree of attack of crown rust compared to 2019 at hulled local populations [F (2,72) = 10.096; p = 0.000] and naked local populations [F (2,30) = 3.401; p = 0.047].

Referring to the resistance to Septoria avenae, high values of variation amplitude (0-15 %) (Table 4) were determined in the variants with oat (V₁) and fava bean (V₂) for the naked local populations.

Concerning the resistance to Oulema melanopa, an amplitude of attack degree of 0-15%, in the V₃ variant and 0-10% in the V₁ and V₂ variants in 2019 in the hulled local populations (Table 4), were noticed.

The degree of attack variability was statistically significant with a high value of the ANOVA factor [F (2, 72) = 4.301, p = 0.017]. LSD test values show significant statistical differences (p-0.000*) in attack variability between variants V₁ and V₃.

In 2020 in the intercropping system, at hulled local populations, the descriptor, days to maturity in V₁ and V₃ variants shows high values of the variation amplitude (134.02-141.00) in comparison with V₂, 134.00-138.00 (Table 4).

The ANOVA F factor for the descriptor days to maturity had high statistical values [F (2, 72) =3.564, p = 0.031], the values of the LSD post hoc test show a statistically significant difference (p = 0.000*) between V₂ and V₃.

Fig. 1 and Fig. 2 show the average values of the agronomic descriptors analysed in 2019 and 2020 in intercropping experiments for 25 samples of hulled local populations and 11 samples of naked local populations. In the hulled local populations (Fig. 1) there is a variability of productivity, the attack degree of oat leaf beetle and crown rust in the two years, their high values being recorded in 2019. In the case of the naked local populations (Fig. 2), the productivity traits and the attack degree of the crown rust showed variability in the two years of testing, with high values in 2019. Also, it is highlighted in both the hulled and naked local populations a variation of the descriptor days to maturity in the two years; the genotypes studied having a late maturity in 2020.

Figure 1 – Influence of the intercropping system on the variability of productivity traits, disease and pest in the hulled oat local populations

Figure 2 – Influence of the intercropping system on the variability of productivity traits, disease and pest in the naked oat local populations

The hulled cultivars (150.40 g/m) and naked cultivars (97.64 g/m) sown in 2019, in the intercropping system, recorded high values of the average yield/genotype, in V₁ (Table 4).

The hydric stress of May-June 2020 manifested in the phenophase of straw elongation and flowering-heading affected the yield/genotype in the case of varieties as well, noting low values in the hulled cultivars (87.21) and naked cultivars (24.40) compared to 2019.

In 2020, in the hulled cultivars as in the case of the hulled local populations, there was a variability of the descriptor, one thousand weight seeds under the influence of water stress in April, June from the phenophases of emergence, flowering-heading highlighted by the higher value of ANOVA factor [F (2.9) – 3.151; p-0.052] compared to 2019. The values (0.04*) LSD test showed statistically significant differences between V₁ and V₃ (Table 5).

Concerning the susceptibility to Puccinia coronata, the naked cultivars were sown in the intercropping system in 2020, showing the variability of the average values in the three variants as follows: 6.00 in V₁, 0.66 in V₂, 0.00 in V₃.

Also, the ANOVA F factor, emphasises high values statistically (Table 5) [F (2, 15)-16.404, p-0.000] in 2020, values (0.000*) LSD test showed significant differences between all variants.

The presence of Oulema melanopa on plants in the intercropping system caused a variability of the degree of attack in both years of testing in naked cultivars with amplitude values of 0-10% in V₁ and 0-3% in V₂ (Table 5).

The ANOVA F factor had significantly high values (Table 5) in naked cultivars from variants 2019 [F (2, 15)-3.509, p-0.056] and 2020 [F (2, 15)-4.953, p-0.022]. LSD test values show significant differences of attack variability between variants: V₁ and V₃ for the year 2019 (p-0.020*) and V₁, V₂, V₃ from 2020 (p- 0.01 *).

Fig. 3 and Fig. 4 show the average values of the agronomic descriptors analysed in two consecutive years (2019, 2020) in intercropping experiments for four samples of hulled cultivars and six samples of naked cultivars. In the hulled cultivars (Fig. 3) there is variability in productivity, the attack degree of oat leaf beetle and crown rust, days to maturity in both years, their high values of productivity and degree of attack of Oulema melanopa being recorded in 2019. In the case of the naked cultivars (Fig. 4), the productivity traits and the attack degree of the crown rust, days to maturity showed variability in the two years of testing, with high values in 2019 for crown rust and productivity. Also, it is highlighted in both the hulled and naked cultivars a variability of the descriptor days to maturity in the two years, with the genotypes studied having a late maturity in 2020. The behaviour of the oat genotypes in association with two genera (Vicia faba and Hordeum vulgare) in the intercropping systems in 2019 and 2020) was characterised by:

– poor plant competition in the variants Avena spp.-Vicia faba, with weed species (Table 5);

– increased the oats yields in V₂ (Avena spp.-Vicia faba) by fixing symbiotic nitrogen at hulled local populations 91.73 g in 2019; 49.11 g in 2020 and naked local populations 69.21 g in 2019 and 20.5 in 2020) (Table 6).

Figure 3 – Influence of the intercropping system on the variability of productivity traits, disease and pest in the hulled oat cultivars.

Figure 4 – Influence of the intercropping system on the variability of productivity traits, disease and pest in the naked oat cultivars.

Similar studies have analysed the increased nutritional potential of the soil (Rodriguez et al., 2020).

Avena spp. genotypes tested were analysed hierarchically by the Ward variance method. Based on the studied criteria, genotypes grouped in five clusters with 20 to 114 members (Table 7). These values were in line with the results of another researcher in domain such as Demirkol et al. (2019).

Table 6
The behaviour of Avena ssp. related to weed presence and yield/genotype in intercropping system

Table 7
Cluster membership on Avena spp. accessions tested in three variants of intercropping system

The amplitude of variation (min-max) and the average values of the 5 clusters showed that in cluster 4, these estimators indicated a high heterogeneity of the morpho-physiological characters, the genotypes tested being classified based on the Euclidean distance into a large group of members (114) with high phenotypic variability compared to the other clusters (Table 8).

The Ward Linkage dendrogram (Fig. 5) showed the maximum Euclidian distance in cluster IV. Out of the 41 genotypes included in this cluster are highlighted in the three intercropping variants from two consecutive years (2019 and 2020) the following: two hulled local populations/Avena abyssinica- SVGB-18444, SVGB-17197, 1 hulled local populations/ Avena sativa ssp. sativa -SVGB-7260, 1 naked local population/ Avena sativa ssp. nudisativa var. inermis -SVGB-184147. As a result, these accessions have a great variety in productivity characteristics, disease and pest attack severity, and days to maturity. They can also be utilized to create hybrid types and drought-resistant crops in dry places.

Table 8
Various traits range values in clusters

Figure 5 – Dendrogram Ward is based on Euclidean distance and includes data from three intercropping experiment types as well as seven agromorphological variables.

Local hulled populations (SVGB-18444, SVGB-17197) of the Avena abyssinica species with diversity centres in Ethiopia can be used in breeding programmes as gene sources for early varieties (Trofimovskaya et al., 1976, Frey KJ, 1991), to improve productivity, (Kanan et al., 1996), resistance to some diseases (Sebesta et. al., 2000). In this respect, in the intercropping experiment with three variants was highlighted by the following characteristics: yield/genotype (20.98-54.7 g in 2020; 10.47-28.3 g in 2019) and one-thousand-seeds weight/ genotype (17.60-35.70g in 2020; 20.60-27.77g in 2019); vegetation period of 121-123 days at maturity in 2020, 136 days at maturity in 2019; resistance to Septoria avenae (degree of attack = 0% in 2020, 3 % in 2019).

Naked local population (SVGB-18417) of the Avena sativa ssp. nudisativa var. inermis species with its diversity centre in China/Mongolia can be used in breeding programmes as gene sources for creation of varieties with naked grain adapted to the climatic conditions in our country (Murariu et al., 2017). In the intercropping system with two years of testing, this access was characterised by: yield/genotype (10.75 /2019; 12.95/2020); thousand-seeds weight/ genotype (12.5 /2019; 20.7/2020), Septoria avenae (degree of attack = 0% in 2020, 3 % in 2019); Puccinia coronata (degree of attack = 1 % in 2020, 0 % in 2019); Oulema melanopa (degree of attack 3 % in 2020, 0 % in 2019); days to maturity (126/2020; 141/2019).

The local hulled population (SVGB-7260) of the Avena sativa ssp. sativa species from Hodosa, Harghita County, Romania tested in three experimental variants was highlighted by: yield /genotype (9.36 in 2019; 33.25 in 2020 ); one-thousand-seeds weight/ genotype (22.83 in 2019; 31.07 in 2020); Septoria avenae (degree of attack 3 % in 2020, 0 % in 2019); Puccinia coronata (degree of attack = 1% in 2019/ 2020 ); Oulema melanopa (degree of attack = 3 %/ 2020/ 2019); days to maturity (124 in 2020; 141 in 2019).

CONCLUSIONS

The varietal mixture of oat germplasm tested in two consecutive years of intercropping with barley and fava bean showed significant phenotypic variability for a series of descriptors like one-thousand-seeds weight, crown rust, oat leaf beetle and days to maturity.

The water intake was different from the emergence and flowering-heading phenophases. The two years (2020 – dry year, 2019 – normal year) of testing determined a hierarchy of heterogeneity, especially for the hulled oat local populations to some analysed traits (one thousand seeds weight, crown rust, days to maturity) and of naked cultivars for oat leaf beetle.

The germplasm of Avena spp. showed high weed competition in variants with cereals (oat, barley) and could be useful for symbiotic nitrogen fixation by increasing oat productivity in the fava bean and oat variant for the naked and hulled local population, making it recommended for cultivation in conjunction with grain legumes in any agricultural exploitation.

The identified genotypes in this cluster (2 hulled local populations/Avena abyssinica- SVGB-18444, SVGB-17197, 1 hulled local populations/ Avena sativa ssp. sativa -SVGB-7260, 1 naked local population/ Avena sativa ssp. nudisativa var. inermis -SVGB-18417) could be utilized to produce genetic combinations for the intercropping system, contributing to the long-term viability of low-input crop production in small-scale agricultural systems and environmental protection in dry areas, in breeding programmes as gene sources for early varieties.

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