CREA DC has been conducted two years of DUS trial for durum wheat varieties located in Tavazzano con Villavesco (season 2020-2021) and Montanaso Lombardo (season 2021-2022) where each of the 250 varieties in exams has been grown up in a plot size of 6 m2 in two field replicates.
The morphological characteristics of the varieties were being assessed in the field or in the laboratory following the CVPO-TP/120/3 guideline. In order to detect the different expression of the quantitative and qualitative morphological characteristics of InnoVar varieties, CPVO example varieties have been used for reference.
We summarised the main information of our DUS trial in Table 1.
Within the two seasons, CREA DC has been collected the meteorological data from the meteostation where the results of temperature (the average obtained from the minimal and maximum temperature) and precipitation levels are shown in Figures 3 and 4.
Although the temperature did not change among the two seasons (Fig. 3); a reduction in precipitation levels was recorded in season 2021-2022 particularly from December 2021 to June 2022 (Fig. 4).
These changes in environmental conditions may affect the state of expression of the CPVO characteristics for the tested varieties, particularly for the quantitative characteristics compared to the qualitative ones; thus affecting the varieties’ description.
In this framework, CREA DC pointed out on the results obtained from the plant length (CPVO n.12; quantitative characteristic) for all tested varieties assessed in each season.
A summary of the descriptive statistics for this quantitative characteristics together with the analysis of variance (ANOVA) performed by XLSTAT (statistical software) is showed in Table 2.
The plant length was significant different between the two seasons, recording lower values in 2021-2022 compared to 2020-2021. This could be the attributed to the dry weather conditions occurred in CREA DC field trial for that season.
Although the differences in plant length were significant, throw the CPVO scale used to describe the state of expression of this characteristic (Table 3), it was possible to identify the note for all the tested varieties. The scale is built up every year using the CPVO example varieties chosen because show a specific note for that character.
In this regard, we figured out that all the tested varieties grown in 2020-2021 (average of 79.8 cm) and in 2021-2022 (average of 77.9 cm) reached the same note equal to 3 (short), leading to not affect the variety description. This result corroborated one of the important requirements that a characteristic must satisfy in DUS testing process, namely to be “sufficiently consistent and repeatable in a particular environment”.
Figures 5 and 6 underline the note distribution for all the tested varieties for the plant length among the two seasons.
The CPVO example varieties are commonly used as reference because they remain pretty stable in the expression for the specific characteristic in exams and help to identify in which range of note the tested varieties fits in. Growing these references varieties and knowing their note from the CPVO protocol, even if it should be confirmed in every growing trial, the tested varieties are placed accordingly. More the tested varieties are far in terms of note for a specific CPVO characteristic and more they are distinct.
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