Mandarin Citrus Breeding for Early Maturity and Low Acidity

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Solution Overview

Problem

There is a need for a new and distinct variety of Mandarin citrus that exhibits specific characteristics such as low spine density, straight-style fruit shape, medium to heavy fruit weight, low acidity, and early maturity, which are not adequately addressed by existing varieties like 'TSUNONOZOMI', 'SETOKA', and 'ASUMI'.

Innovation Solution

The development of the 'HAYASE' Mandarin variety, which is asexually reproduced by vegetative propagation, combining traits from 'TSUNONOZOMI' and 'SETOKA', resulting in a tree with a spindle-shaped leaf blade, flat fruit apex, and high sweetness, and exhibiting characteristics like few spines, no pollen, and early fruiting.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If existing Mandarin varieties like 'TSUNONOZOMI' and 'SETOKA' are used, then they have established fruit production capabilities, but they exhibit high spine density, curved-style fruit shape, and high acidity that are not desirable

Engineering Contradiction:

Improvepeeling easeVSAvoidspine density

Core Design Contradiction:

Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The invention combines traits from two parent varieties 'TSUNONOZOMI' and 'SETOKA' through controlled crossing and selection to produce 'HAYASE' that merges desirable characteristics (low spine density, straight-style shape, low acidity) while eliminating undesirable ones (high spine density, curved style, high acidity)

Inventive Principle:

Principle #5Merging (Combining)

2Productivity

If existing varieties are used for fruit production, then they provide adequate yield, but they have late maturity and high acidity that limit commercial appeal

Engineering Contradiction:

Improvefruit yieldVSAvoidmaturity time

Core Design Contradiction:

ProductivityVSLoss of time

Solution Approach 1:

The invention changes key genetic parameters through breeding to achieve early maturity (January harvest vs. later varieties) and low acidity (0.90 g/100ml vs. higher in parent varieties), while maintaining productive fruit yield through optimized fruit set and development

Inventive Principle:

Principle #35Parameter changes

3Weight of stationary object

If existing varieties like 'SETOKA' are cultivated, then they produce heavy fruits, but the fruits have high acidity and curved shape that reduce marketability

Engineering Contradiction:

Improvefruit weightVSAvoidfruit shape

Core Design Contradiction:

Weight of stationary objectVSShape

Solution Approach 1:

The invention applies local quality by developing distinct regional characteristics in different fruit parts: the apex is flat (not curved like SETOKA), the style is straight (not curved), and the skin color is bright orange (JHS 1305), creating a uniform and attractive local appearance throughout the fruit surface

Inventive Principle:

Principle #3Local quality

Data Source

PatentUSPP37170P3<i>Citrus </i>l. plant named ‘HAYASE’

Publication Date: 2025.12.23 NAT AGRI & FOOD RES ORG

AI summary

A new variety of Citrus sp. tree ‘HAYASE’ that has medium tree habit in-between upright and spreading, spindle-shaped leaf blade with acuminate apex and acute base, vestigial wing, fruit with high diameter/height ratio (average 1.31) and medium to heavy weight (average 152.3 g), no neck, a flat distal part, bright orange (JHS 1305) skin color, thin peel thickness, easy to medium peeling, deep orange (JHS 1307) color when fresh, juicy when fresh, high sweetness, very few seeds, early maturity, and low acidity.